I'll throw in my two cents....
"Macho" guys, or Type-A personalities need to feel in control. They constantly have to reassure themselves that they are the biggest, baddest, awesomest guys in the room, and that involves making sure that all the other guys have a constant reminder that they aren't.
Though, as far as the non-macho guys not fighting back, that's a dangerous mindset. In the Marine Corps, I was on guard duty at the barracks one night. Military Polics brought back two of ours, and they had been beaten senseless. So I'm thinking, "They messed with the MPs". You don't mess with Military Police. You just don't.
The snickering MPs told us that this wasn't the case, however. Seems these two macho Marines had seen a little skinny guy in a club with a very attractive woman. They decided to let him know in no uncertain terms that they didn't think he deserved to be with this very attractive woman. Cue some insults and eventually, the little guy had had enough.
Little guy held two black belts in different martial arts.
Cue the two Marines getting their asses kicked up between their shoulders. The CO didn't even punish them, not really. He figured the lesson was punishment enough.
When I go out, it's not the loud, obnoxious, macho guys that I keep an eye on. It's the quiet guy, sitting at the bar, seemingly minding his own business.