Is a standard black and white?

As a leader, given this situation - food first! I'd consider it part of the mission. Mission accomplishment includes welfare of the troops.

I would feed them Soldiers, sometimes you have to use common sense!!!

Misleading subject: the standard is to accomplish the mission and take care of soldiers.

The standards that specify the length of their shoelaces is below the one that tells you to feed your folks.

There are priorities. It isn't a matter of picking and choosing, it's more a matter of prioritization. When you have time, when you have resources, some lower-priority items can be crossed off. Until then, beans and bullets.

And I never saw a tiny FOB mess that closed on the clock; they'd open and serve until everyone was fed or they were out of chow.

This is a tee-ball question, give me something tougher.

I would let them go eat first, them have them shave

My mission and my men. 2 basic responsibilities. Let them eat and take the butt chewing later. Make them shave immediately afterwards.

They would eat! Bottom line

As it applies to the serving period the dining facility manager can allow the soldiers to come in after the period is over due to their mission. The platoon leader/commander usually can give insight to the soldiers and allow them time to get food whether it is by having them take their food and go recover from the mission while still giving the dfac manager what they wanted as the soldiers would not have to be in their dining facility and still getting the soldiers their food.

I would shave from my helmet while I ate and when questions came up I would explain it. I would carry my razor and shave with butter. Thank you for your service.
Sincerely,
Destroyer

Hey look you have to eat to keep going I remember getting off 24 hour CQ and going straight to the chow hall eating then going back to the barracks and going to bed. Would not have been able to fall a sleep if I did not eat

The majority of the replies here seem focused on the choice between eating or not eating, and of course, the choice in that scenario is clear. Let them eat. What is not so clear are the circumstances, and the potential unintended consequences of hastily made decisions. I'll play devil's advocate for a moment, and give a different point of view that doesn't see just two choices. The rationale for not allowing dirty Soldiers into a DFAC is based upon the idea that a DFAC must be a clean environment and enforcing hygiene is a force protection measure put into place to preserve combat power. So the first question I would ask when confronted with conflicting priorities is this: is there another way that satisfies both requirements? One possibility is the good old MRE. It certainly isn't everyone's first choice, but it keeps Soldiers fed and prevents the potential spread of microbes in the DFAC. Another possibility is to have hot chow brought out to the Soldiers on to-go plates. This would give Soldiers hot chow and still keep the DFAC clean. I think the broader issue is one of leadership. If I'm on a long patrol and chow is a priority for my Soldiers, then I'm going to reach out to the leadership at my destination to make that happen without storming the DFAC as though I own the place. Lots of talk in the comments here about common sense, but not as many mentioning planning, leadership, or creative thinking. With a little bit of each, you can arrive at an acceptable solution without jeopardizing the health of an entire FOB.