My dad said when he left the stadium in Arizona in 1992 he had fans getting in his face screaming the worst curse words imaginable. So I'm guessing he'd toss in a vote for U of A
Only almost fight I ever experienced at a football game was at a Husky tailgate (Montlake) with an eager and fratty OSU beaver who made an inappropriate reference to my wife's tits. But that's all I've ever dealt with personally, though I've seen many a fan misbehave (including our? own). I personally do not talk shit with strangers at games. Seems like a bad idea with little to no upside. I also mostly sit/sat next to a former Husky who people often recognize, and I think that tends to subdue the shit talking a bit as a general matter.
Today I'd probably just high five the guy in agreement over the comment and say "you have no idea buddy." But I was young with a greater tendency to waste energy on non-sensical matters. When you cross 50 you become much more discerning about what does and, just as importantly, does not matter.