No, I am not proposing a Sikh regiment in the US army. And Sikhs in the US army have very few disciplinary problems, so if somebody has heartburn with their turban or beard, it would be them that has the problem.
And no, uniformity has little or no meaning, beyond uniforms, because soldiers are tall and short, all races, several religions as well as atheists. Many black male soldiers have “shaving profiles”, caused by Pseudofolliculitis barbae, which means that they cannot shave every day, and even so, their faces are covered by scarring.
Having a turban and beard becomes even less a problem the higher the rank of the Sikh. The last one I saw in the Army was a Master Sergeant, Green Beret, in the Special Forces Reserves.
Sikhs are obviously a discipline problem that is why they are always rabble rousing to change the U.S. Army, and how many are serving, 3, a half dozen? how many? Also, why does that Green Beret one always get mentioned?