Why does the Army appear to have a discipline issue with the lower enlisted ranks?

The problem is that the Army, as well as the Air Force cater to the lower enlisted. Instead of "Putting their Foot Down", they cater to them. They know nothing will be done to them.
When I first went in (1969), if you didn't do what you were told to do, you got your ass handed to you, that is after the punishment phase.

Their are several factors to your statement/Question. One being that the Marine Corp has a great pool of people that are competing for rank and job slots. Second the Army looks a non NCO's enlisted as replaceable along with rank of E-1 through E-4 as auto promotions. What is also a contributing factor is that the Army changes its retention standards. This is based on slots that are vacate, along with its budget that is authorized by congress. The Pentagon often reviews its personnel needs vs equipment needs to keep within its operational budget,

Sir, I see that this was posted 10 months ago. I served in the Army from 76-87, two tours of Korea, 1 in Germany. Although my observations are old, I have had 32 years to reflect. I hope my comments help.
Vietnam devastated the Army officer corps. Discipline was left to the NCOs. Minor infractions were dealt without UCMJ action. They were dealt with by extra work details, restriction to barracks. This kept career ruining ART 15s down. The NCOs were able to show that they genuinely cared about the soldiers assigned to them.
This started to change in the 80's. As the officer corps grew stronger the NCO corps grew weaker. UCMJ actions became much more common, leading to a decrease in morale. From my observations, for brevity general observations, NCOs were focused on the next promotion, officers were focused on the next posting, and the lower enlisted were ignored.

This is an interesting question, and one that is not new. Those of us who served in the late 70s and in the 80s had similar challenges.

This is a leadership challenge and young leaders have to be committed to leadership 24/7. Setting and expecting high standards is the start but LIVING those standards each and every moment is the key to success.

I think that it has it's roots in spending so much time on the battlefield with a limited, and non-specific, strategic objective, no truly decisive engagements and a lack of demonstrated national will in the endeavor. A war that started out with a call to arms and a visible rallying point is now being fought by soldiers (E1-E5 and O1-O3) who were not old enough to have their own emotional responses to the attack on the World Trade Center. Very reminiscent of the Vietnam War.

Soldiers commit to fighting and dying, but no one at home has any real skin in the game except parents. In fact more and more of the service age youth see it as an errant cause and choose not to participate. In 2001-2003 a large number of young people wanted to do something because the smoking towers were burned into their memories, that is not so today, so the quality of recruits is lower than in the early ‘00s. In the late 70’s and early 80’s we had an equally, possibly lower level of quality and motivation.

It took a combination of NCO’s willing to hold the line every moment of every day and backed up by officers who want to see them do it. And there are a lot of us out there. My PLT SGT and Asst PLT SGT were attacked in the barracks because they were holding the platoon responsible for nasty looking rooms two weeks before I arrived at the battalion. They knew the attack would happen and went into the barracks anyway. They were not because looking for a fight, but they were not going to allow the troops to intimidate them either.

Three E5s and two SP4s lost two pay grades and we chaptered the three E5s out of the service with other than honorable discharges. Interestingly, one of the former E4s regained his rank then earned his E5 to replace his E6 who was a week leader and had allowed the ill-disciplined behavior in the first place. I like to think that because my PLT SGT and I were willing to hold them to high standards and led with high standards for training and performance this young man became all he could be.

The key is, and always has been, leaders who set high standards by demonstrating those high standards. In my life after the military I have found that setting, demonstrating, and expecting high standards of performance works even with delinquent youth.

I will add to this that in the early 80’s the military was willing to allow the removal of poor performers while the DOD was willing to only recruit quality people and the Army was focused on empowering young leaders (Corporals, Sergeants and lieutenants) to lead and to identify their best solutions to the problems they faced. You don’t need to be the biggest baddest person to ever wear the uniform, you just have to seek excellence in yourself and your subordinates and be the last one to quit.

My insight is as follows Sir - discipline in the military has different meaning then anywhere else. I.e. immediate attention to orders, GO’s, courage under fire, physical fitness. The list could get quite long. I’ve served in both active Marines and Army and I’ve noticed the same thing you have. Bluntly I think it’s largely due to political correctness. The Marine Corps has an attitude that all they do is “kill, kill, kill!” Every Marine a Rifleman. They’re pretty good at instilling that attitude as well. It’s cool to be truly gifted at ‘closing with and destroying your enemy.’ The Army on the other hand is has way too many different mind sets it struggles with. The large portion of Soldiers I interact with and get to know join because they have nothing else to do, or because they initially thought the gun hoe Army they saw televised inspired them and then they experienced the actual Army. NCO’s are largely tasked with instilling discipline and without a singular, widely accepted mindset, it feels like the NCO’s and Soldiers don’t know what’s expected of them so they don’t try as hard.

As well, four years in the Corps I don’t remember participating in a single parade, publicity march, or other social media formations. In the little over 2 years I’ve been Active Army I’ve had to cancel planned training more times then I’ve been able to execute training I’ve tried planning. The Corps and Army practice different priorities a daily basis and I feel that’s what you’re seeing as the discipline issue sir.

possibly the lack of respect due to their up bringing, many see other soldiers mouth off and that isn't right, so therefore the issue

You Sir are a new officer in your "All New Army" as it was posted and fed to us up until my retirement. I'm a retired NCO and understand your frustrations to the "T". Problem is my man, you joined an ASS KISSING Army where the lower enlisted as well as the NCO ranks have come to think, "believe AND BEHAVE in a manner where they feel you listen or go sit in your corner bc I have more time cleaning latrines than you have active duty". Same shit, different military. Stand your ground, enforce discipline from "TOP" down and ensure your unit has faith in you. A couple "let-go's" are cool. Major infractions punish but, easy brother, you still want them. Share kindness in your command and punish those who refuse to be or are otherwise disruptive. Just an ol' time NCO Sir!!

This "discipline" issue began post Viet Nam, late '70s early '80s, when some "thinkspank D.C. consulting firm" bilked the DOD a couple of million dollars, convincing them, the DOD, that it, and its subordinate branches should adopt a "Corporate" like image. Something about reducing the images of "The Atrocities of War" on the Services... Hope they like what they engineered, removing the ability of the Superior Officer or NCO to be Judge, Jury, Executioner, and Confessor, no paperwork required, with discipline, respect, and cohesiveness restored, all in the space of a minute.

As others have said on here, the discipline and respect as well as customs and So forth are quite often at Company and or BN level. We could talk about this all day long as I was firm believer in leading by example and if you are an NCO then you damn well better act the part or will be replaced. Just as a commander can be removed, enlisted soldiers within a company can be just as easily if not easier. When I joined in 02’ I stood at parade rest as we are required to do, not asked nicely to do! From 02’ through my time as a 2nd LT, 1LT then on to Company Commander, I watched before my eyes the as the lower enlisted went from showing respect and completing the mission to needing their hands held and somebody watching over them. Not in all cases was this true but the majority of what I saw was this occurring. On more than one occasion after telling my 1SG I wanted the building cleared as I could not hear myself think, the troops and even some NCO’s disregarded what they were told. At said time I walked out of my office and dropped the hammered that NCO’s better act the part of an NCO or come let me know you want out so I can get your paperwork started as I had the full backing on my BC. It took the soldiers a matter of seconds before the building was cleared.
The point of this story was the fact that lower enlisted are going to follow suits right behind NCO’s, and if they see them doing or acting they please the lower enlisted will follow their lead. As time goes on these lower enlisted move up to NCO’s and continue the cycle. Additionally I believe. Very strongly that this mindset starts now in Basic Training as opposed to years ago when Basic Training was a place that set the ground work for the making of solid soldiers which will then move on to their respected unit and hopefully continue that cycle.
As one other person stated on here, a units leadership( regardless of size and structure) is responsible for instilling discipline within the ranks.
I will say that I did always like and very much respect the USMC for the discipline of their marines, regardless of rank and or title.
Best of luck on your white paper.

When I got out of the Army in 1971, just back from Vietnam, (3 years in). I saw a different Army materializing, so the choice for me was to get out. I walked into a mess hall and saw changes that told me it wasn't right for me anymore. The current situation is just one of many problems I saw coming, the new army as it was being touted.