So I just saw a story that the DoD has changed uniform regulations to allow for military members to wear turbans, scarves, beards, and whatever other religious things they want while on duty.

Now, while I just read another article about this, and apparently any such allowances would have to be granted by the units' command, and that they must not interfere with the service member's safety or health in any way. Which makes sense. BUT:
Military uniforms are called UNIFORMs for a REASON: they're uniform! Everything is interchangeable and smooth, every action repeatable, every part interchangeable. It doesn't matter if you don't like wearing a cover, or-- oh, for you non-Marines (far too many of you are out there...) a "cover" is your uniform's hat-- or whatever, guess what? It doesn't fucking matter; you're wearing a cover. You like having your hat on inside? Too bad, you take it off the moment you set foot inside that door.
These are basic things, things which reinforce the importance of unity and uniformity. Every man and woman needs to be able to take any other warrior's place if the need should arise. That is the mentality which supports most everything in the military. In boot camp, every single rack is literally measured an exact distance from each wall; from each other; from the Drill Instructor's Highway; every footlocker is stacked precisely; each and every combination lock is pointed to "0"; every rack is made exactly the same way. That way, if something happens to you, anyone in the area can help you out.
Find one method which works and can be replicated en masse, and that becomes military doctrine for the next century, because "we know that this way works, and we would much rather take the confirmed way than take chances with how you want to do things." And what happens if you're in camp and there's an emergency, say you were stabbed in your rack, and-- OK, "rack" is your bed-- and someone came rushing in to save you. They had everything needed, but they tripped on the footlocker and fell, cracking their head on the rifle that wasn't where they'd expected it to be, and now you're going to die. So, everything is done the same way. Nothing is mixed up or lost or confused, because everyone knows exactly where everything will be in everyone else's space.
This stems from combat-- a concept which I fear is being lost in the military, that policy should absolutely reflect those ideals for combat; the things learned in combat should absolutely imbue every action of the organization. In combat, every man knows the job of the man above him in rank/position; therefore, if the top man gets killed, the unit isn't necessarily lost, because immediately there is at least one other person there who knows how to lead them. Therefore, EVERYTHING that you do, everything you see, everything you make, must be replicable and repeatable by someone else, so that when you're in combat it's totally automatic to learn what to do in your command's place, and make it as easy as possible for the man below you to pick up in your place. Say a large portion of a unit's command was wiped out in combat; a large-scale ingress of officers and staff would be needed to replace them, and the predecessors wouldn't be there to teach their method of filing or anything like that. So, if everything is done the same way everywhere, anyone can theoretically step in and take over if needed.

I'm rambling; I'm not even sure if this makes any sense at this point. If not, say something; I'll try to edit it when I'm actually awake sometime, make it more... intelligible.

But anyway: so, yes. Everything is, more or less, interchangeable.
And everything must be efficient and effective. This is why men must keep their hair very short-- because, for so long, men have been the only ones officially in combat roles; so, what was best in combat was determined. Uniformity is enforced, and efficiency is greatly increased. For women, the rule is essentially that the hair cannot interfere with wearing any military headgear- soft covers or Kevlar (helmet). Uniform, and effective.
Facial hair has been almost entirely banned. Special Forces units (MARSOC, SEALS, Delta, etc.) are permitted to grow facial hair, either to blend into the local populace of their AO [Area of Operation] or to minimize their efforts and footprint (waste, time spent, etc.) with shaving. But facial hair is generally banned, as it can easily harbor all kinds of dirt and grime and festering infections, and your face is NOT where you want an infection! So, facial hair is kept *minimal*, enough to discourage it entirely; hair on top of the head is kept rather brutally short, with rigid regulations as to the style and shape-- again, to enforce uniformity.
But now, you're going to be allowed facial hair? Oh, no. No.

Because now, we'll get to the final point. This is a little bit of Marine snobbery, but I do think it's true: EVERYTHING should be *about* combat. I say this is Marine Corps moto (motivation, for you civilians) because the Corps, on the closer-to-combat-infantry levels, is still focused on combat. The Corps is overwhelmingly focused on infantry MOS's; the majority of Marines are 03's (infantry). The Army is rather the other way around; but the Army has a massively different job than the Marine Corps, and as such should be more widely based. The Corps is the attack dog, the shock-and-awe punch; we're born of naval-based assault, i.e. "putting large and prepared ground forces in places you didn't expect", and Marine Ground, Air, and Artillery forces all work together very closely. Marines are a heavily concentrated attack on every level. We do less with more- "improvise, adapt, and overcome!"- because advance attack troops are often out beyond resupply and support. We train to achieve maximum combat efficiency- "every Marine a rifleman." But as top brass lose sight of that reality- they, sitting in their offices in comfortable Washington, D.C.- their policy shifts, it changes, to better conform to what they see of the Corps (those cushy offices and high-priced suits). Those changes are uniform-wide, so what they see as being best in their situation winds up being enforced halfway around the world, in a situation which is NOTHING LIKE theirs, and it distracts the focus away from combat, and onto the rulebooks.
The basic rules in the Marine Corps are based on combat; most every uniform rule can be traced back to its combat-related origins. For example, in Marine Corps Boot Camp, you are required to only ever hold your cup in the chow hall in one way: with your forefinger and thumb circled around the base, and your other three fingers curled fist-like beneath the base of the cup. It wasn't for some time that we learned why: that is precisely the drill-correct position to hold your fingers when pulling the bolt back during drill, at the "Inspection Arms" movement. It was so ingrained in your head already by then that it was natural. Everything in boot camp was like that, and quite a bit of the Corps in general is much like that. Combat-related movements, thought patterns, everything, all of it embedded within other routine motions, so that you don't even realize you're learning. It's the Karate Kid, only Mr Miyagi won't yell at him- Mr Miyagi will chew you the fuck out, scream at you until you feel like the dumbest, most worthless piece of shit on this Earth, and then make you do it all over again... all night. But then, after a week, suddenly it's all ingrained and muscle memory and automatic. So when you're riding in a truck on your first time outside the wire, and your truck gets blown off the road in an ambush, you aren't desperately and uselessly flailing at your rifle and missing every shot and endangering everyone even more; it's instinct. You've been doing this every day for the last two years, even if you didn't know it.
So, that's a long rant to say this: the best possible way to live in and through combat should be the basis for every rule and decision made, at least in combat elements. I.e., the entire Marine Corps, some of the Army and the Navy, a few Coasties, and NONE of the Chair Force. So if pilots want to wear bears and turbans over their club blazers, whipped in the wind as they zip along in their new sporty convertible, then that's fine. But Marines MUST stay focused on fighting.
I believe that that's a large part of why General Amos had so little respect from the day he stepped in as the Commandant; the basic Infantry Rifleman, 0311, and all of the 03's, and everyone who worked closely with 03's and thus picked up their mindset (i.e., most of the Corps-- except the Chair Wing) felt like the command had forgotten about them. The focus wasn't on them; the focus was on "looking professional for photos, so that Mommy and Daddy will be so proud of their little warrior, and won't complain to the Press about the Marine Corps being bloody and terrifying!" And while maybe that sounds selfish, like a child throwing a fit for attention, realize that this comes from 03's. Riflemen, machine gunners, Recon, snipers, the guys who are literally pointing weapons in the face of the guys who are trying to attack this country. I think that they earned a little bit of attention, especially from the Corps' command.

Anyways. Ranting again. Sorry.
Point being:
Uniforms should be, must be, UNIFORM.
Because, uniforms reinforce combat standards for everyone.
And, combat standards for everyone means everyone has the potential do survive and thrive in any situation where the command has been wiped out (combat).

I'm going to stop myself now, before I type another eight pages because I just keep thinking more things, and trying to put them down.... The train of thought isn't on rails, it's more like a 4-wheeler, one that lost its driver but has the throttle pinned wide open, and just runs around and around and around.
There we go again.
OK, 'bye.