People are railing on Shiz because of the garbage he's pulled in the past. Great, he finally beat a heavily favored guy that's been beating him since high school. If he didn't have the reputation that he does, then nobody would be talking about his celebration. The fact is that his past made that celebration over the top.
It's the same thing when you watch the NFL. If some dude scores a touchdown and does a dance in the endzone, but doesn't have a bad rep, people don't care much. You see T.O. in the endzone, and the celebration becomes excessive and stupid (yeah, T.O. does go over the top, but I just threw a random name out there).
Bottom line: if it was someone like Weiss, it wouldn't have mattered much because he hasn't acted like a douche for years. Coming from Shizzer, people hate seeing a guy with his attitude and demeanor win, so they call him out.
I don't care either way about this celebration, or Mr. Shiz, but I just think this is one of the main reasons people are making a big stink.