Why don't all members of the Air Force have to be fully qualified to be a rifleman in case of hostile events?

I was Air Force during Vietnam. I had to qualify with an M-16, PT, Combat Training. Why in the world would not every branch of the service have to do this?

I achieved expert marksman status in the Air Force during basic training in 1950. I was not aware this training was stopped.

There are many ways to fight

I think you are full of shit, you haven't been around very long or read your History. My career field AFSC 605/2T2 was trained in all weapons, tactics: from shotgun driver, SOS, CCT or whatever unit, you happened to be assigned to. Yes, I came in 1983-2004, ever hear of Airfield Defense School? We were the guys that put you on the plane, either at the DACG or Pax Terminal, and when we were fired upon, and no one was around, we guarded the airfield when no AS/AP/SP/SF were available, we did our own. The big Boy Scouts (Army) taught us how to fire those nice big toys, Rock On 1/506!
Anyway, shut your mouth until you get some experience. Another thing, where is the common sense? Do not fucking get me started.

If you wanted to be in the military, you shouldn't have joined the Air Force...

Combat Comm, Red Horse, Forward Air Control, Special Operations Airmen all train with their weapons and are tasked with their own defense and combat operations because they operate outside the big protected Air Bases. Because everyone only sees airplanes they forget the handful of Air Force personnel on the ground in the combat zones.

When I was in the Air Force, we did have augmentees who filled in in emergency situations. They were not well trained and where just an extra body to fill emergency positions. Everyone should at least be trained in basic weapons use.

Don't know about now, but back in '61 we had weapons training then. Granted, it was with the M 1 carbine, but that was typically the weapon issued to behind the lines troops.

I was in the Air Force during Vietnam. Not only did we receive training with the M-2 and the M-16, I made expert with the M-16 and was highly proficient with a .38 caliber Sub Nose. Every crew member on a B-52 had a .38 with him and knew how to use it. In basic we even saw some training with a 50 caliber machine gun. What has changed?

Absolutely true war story: OIF, 2003 - I was the Logistics Officer for Marine Air Control Group 38, stationed at Al Jabber Air Base in Kuwait. As the offensive was winding down, USAF units stationed there began moving forward to Talil in Iraq. Shortly after this began, I received a call from the 3d Marine Aircraft Wing Logistics Operations Officer, asking if any of our units had any "extra machine guns". Since we had exactly what we rated, I laughed "No! Who the hell thinks we might have 'extra'?" He replied that the USAF wants to arm their convoys, and since they don't have any weapons...not even rifles...(except for the Security Forces stationed there), that they were asking around. IDK if they ever got any machine guns.

Flash forward to 2010 at Camp Leatherneck in Afghanistan. I saw a USAF SSgt struggling with unloading his and showing clear before he went into the chow hall. He seemed to not have the first clue how to operate the pistol. Add to that the fact that he was trying to hold a water bottle at the same time, and I had to step in. He refused my help, and I moved on, hoping that any negligent discharge wouldn't wind up hurting someone.

A bit of a sad testimony when our members of our Armed Services don't know how to operate those arms.

The Air Force never learned the lesson of Vietnam when Air Bases routinely over run. Every member of the Military should be full qualified with a personal weapon. Intent of a Branch mission is one thing. Reality on the ground is a separate reality.

I think you are spot on with your assessment of the AF's weapons training and qualification. Once your aircraft is shot down its you and the enemy and your service pistol. Same goes for a forward operations area that is suddenly over run by the enemy. You get up you grab your rifle and ammunition and you go fight the enemy.
My son's a Capt. Flying KC-10's and he was taught at home by his G.I. Daddy to shoot with a single shot Winchester .22 and then the Colt 1911 and the M16A1 Rifle and later the Beretta and the M16A2 Colt Rifle. He has been asked to be on an AF pistol marksmanship team but with his ops tempo where it is, he has no time right now to do that.

Marksmanship begins in the home.

Because the Air Force is a country club with Marines on the outer perimeter to protect them? Sorry, couldn't resist..... but you left the door open.

The Air Force spend their money on creature comforts like great food in their DFAC, cable TV in every barracks room, 4 star hotels while on TDY. I doubt they care about spending money on ammo. They don't even have a serious PT program, do they?

To be fair with my AFSC the running joke is if we have a weapon, everyone else on base is dead and we're fucked anyway.

Why? Probably for the same reason Security Forces or Hospital personnel don't go out and wrench on aircraft. Airpower is about taking the fight to the enemy's center of gravity, shutting down their ability to prosecute their plans by destroying the means to that end. Everyone has a role to perform to that end.

I don't have time to fight the enemy. I need to get this damn Aircraft off the ground and out of here. That's what the Army and Security forces are for. Give me enough time to get that bird in the air and out of here. After that, I can pull a trigger, but do you really want me to? I might see that 16 once a year.

Because some dumbass in SAC Headquarters convinced other dumbasses that they coud save money by not arming all military personnel assigned to the bases. SAC was the leader in this idea.

My leadership class project addressed this exact issue back in the 90's. Although our fellow Reservists were supposed to qualify every three years, the average maintenance airman had not done so for eight. Although they individually felt confidence in their own abilities, several expressed more concern about fellow troopers than a potential enemy.
Although airmen aren't expected to withstand a protracted siege, we should at least be able to "hold the fort until the cavalry arrives".

Is this a new thing that other specialties are not being trained to use a weapon? When I was in there were times that I was at the range teaching others how to use different types of weapons. I also was security/ law enforcement forces. I spent a lot of time on the range because of the number of weapons that I was qualified on so I was training others on techniques of cleaning and stripping it down to put it back together. If they have stopped this then they have made a mistake it is good for all members to know how to handle a weapon.