I suspect that the excuse offered will be something along the line of “we can’t be revealing the faces and identities of our undercover agents” or some claptrap like that.
You raise a good question here. If it looks like a thug, walks and talks like a thug, and wears a mask and/or bandana like a thug?
Forget the steeeenkin’ badge they might be carrying, it’s a THUG!
Let’s see. Wearing a mask so that one might avoid prosecution is a valid excuse, but wearing a mask so as not to compromise the identity of an undercover officer is claptrap. And the officer is a thug as well as the perp. My, what a thrilling journey into the land of moral relativism! Next time you’re in trouble I suggest you call a Libertarian or the ACLU. Then you can kiss your ass good-bye with a warm and fuzzy feeling.