Should the saying "every Marine a rifleman" be changed?

No, for all of the reasons stated herein.

Its an expectation that every Marine, including cooks and bakers, be able to wield a weapon when need be. And as a former Marksmanship Instructor, while a lot of our non infantry Marines aren't the best shots, some of our infantry Marines aren't the best either. But damned near everyone can be trained up. It's all about the leadership wanting to devote resources.

After 20ish years as a support type, I do agree that every Marine is a rifleman, just as I also agree that not all Marines are infantrymen. I was a Utilities Marine, I made sure that everybody had power when requested, water when required, and HVAC when necessary. My job was to support the infantry. I understand that. That doesn't mean that my responsibility to my Marines training suffered any less. We trained with weapons at every available opportunity. That doesn't make us infantrymen, that reinforces we are riflemen.

Where the hell is the eye-roll emoji?

I have been out of the marines since 1994. In December I retire after 16 (additional) years in the NG. I STILL HAVE BETTER RIFLEMAN SKILLS THEN MOST of the NG soldiers I serve with and better rifleman skills then many of the infantry in the NG units in my state. I still know more about being a rifleman then many current service members. I did this as a then 2531(now 6800 series I think radio Operator) assigned to A Co 1/3. That time coupled with my Boot Camp time did this. Yeah i am not a "rifleman" but I am a rifleman and will never forget those lessened learned as a "non-rifleman" Marine. So my vote is for absolutely not doing this ever. It makes the USMC unique.

Ok here is my two cents, he was a terminal lance corporal last promotion was four years ago, you guys are spinning up for nothing. He is trolling to see what happens when people respond to his post. Don't give him the satisfaction.

As a concept "A commonly thrown around term is "Every Marine is a rifleman" is accurate, in reality, the majority of the non infantry soft marine MOS service members I met, had not touched a rifle other then to annually qualify with it since they went to that initial basic course.
So yes, on the 29th day, "Every Marine is a rifleman" as everyone of them have attended the basic rifleman course.
3,5,10 years down the road, that Marine cook, signalman, Network operators is not more a skilled riflemen than their Army counterpart. Both can generally remember which way to point the rifle , load, reduce stoppage and engage a training target... But having met and worked with hundreds of non infantry Marines...Id be no more confident, provide any less supervision, guidance and over watch to a SSGT Marine cook I had to put in a tower on guard then I would a SSG Army Cook in that same tower. ... For sure basic rifle skills like marksmanship beyond a 25meter target will come back faster to the marine that has at least had long ago some on hands training...Vice the Army SSG cook that likely has never done more then shoot the pop up range a few times over the years, assuming their unit does not use the common fall back of a 25 range.

NONE of that is meant to talk down about Marines or Army Cooks for that matter .. They have a job, and they are good at the job, because they train on it every day. But no one being honest with them selfs is going to say a person that did 28 days of training 3, 5, 8, 10 years ago has retained any significant measure of that basic training all those years later.

I agree. It's wishful thinking at best, poor marketing at worst. I get the underlying intent, they want all Marines regardless of Occupational Specialty to be able to pick up a weapon on the battlefield and be able to hold their own. That might have worked as an expectation in WW1 thru Viet Nam, but not anymore. Understand the limitations and work them into mission planning. Knowing that every swinging Dick and Jane in cammies IS NOT a war-fighting machine is half the battle ;)

I came to kill, label it whatever you want and at the end of the day, in combat it is kill or be killed! As Marines if we can't kill then we are wrong and must fix the deficiency.

Everyone in the Army has an unofficial MOS as an infantry man. In case of emergency, grab your rifle.