[Jewbacca]

They look a little green and pretty.

In seriousness, I understand the need to shave a beard in modern combat, due to chemical warfare and the necessity of masks --- I had to shave down to 3mm beard in the Israeli military because I was a pilot and needed to secure my mask, but going completely beardless is a form of cross-dressing in Judaism and specifically forbidden to shave (as opposed to cutting very closely). (This is the background of the on-going joke exchange you posted in the middle of.)

I read somewhere that Western Gentiles shaving was fairly new -- and, while not unknown -- Roman Centurions shaved, for example -- beards were more the norm than not. WWI and chemical warfare was really the impetus for kicking off the clean-shaven look in the West.

[NorthMountain]

due to chemical warfare and the necessity of masks

Occasionally, my job requires me to work in a certain location ... and then I have to shave. Gas mask: I may never need it, but if I do I'll need it right bloody now. I normally have about 1/2 to 3/4 inch of beard, probably "closely trimmed" by your standards.

Google up photographs of soldiers in the American "War Between the States". To my knowledge, that was the first war to be photographed; soldiers went from completely clean-shaven (perhaps 17yo kids) to some fairly spectacular beards. All the men in the picture you posted would fit right in either the Union or Confederate armies.