That was the justification for requiring clean shaven troops when I was in. Soviet battle books contemplated use of chemical weapons, so I imagine Putin's might as well. Mustaches have always been allowed because they don't interfere with the mask seal.
Dunno how many exceptions have been granted recently...I wasn't aware of any exemptions, medical or otherwise, when I was in the Army, and my units had many African-Americans, so this may be much ado about nothing.
This message has been edited 1 time(s).