Im not gonna read all this nonsense just going to say this...
Guys that big are compensating. Most guys with big mouths cant fight. All bark, no bite. Sure theyre physically strong but Id be willing to bet that none of them know how to throw a punch, which is why they roll in packs. You dont need to be big to fuck someone up... hit him once, hit him right, hes going out like a light.
Also remember one other thing, there are no referees, there are no judges, there are no scorecards, you cant get disqualified. If one of them touches you, grabs you uncomfortably, you grab him uncomfortably - grab his nuts, squeeze and twist. Furthermore, confidence works, so does crazy. Personally, if someone gets tough with me I stare them down and give them a smirk like "yea, ok, I wish you would". The other option is, get loud, get in his face, yell a little, startle him, throw a temper tantrum, crazy works sometimes.