There's a lot of language being expended here, but none of this really justifies what the restaurant did. Which servers were victims, or relatives of victims of police violence? The cops were "armed to the teeth"? Police officers typically carry sidearms, perhaps Tasers, pepper spray, collapsable batons, etc... Typically they leave their shotguns in the vehicle.

Rationalizing the restaurant's action by claiming strong boundaries are healthy doesn't mean anything. Said boundaries must be intelligently applied & fair. Suppose the restaurant declined to serve Muslim customers because some of the servers had lost relatives in the WTC attacks (or were simply traumatized by having watched them on TV)?

If the servers were really that upset, then the manager or owner could have stepped in to serve them. Their business is taking a hit now, & give the margins under which food businesses operate it might not recover.