Someone walks up to you in your job, gets 2 inches from your face and says " you are a piece of crap". You might give them a little shove at the least.
Okay. Big difference.
Someone walks up to you and puts themselves 2 inches from my face, at that moment I believe I am about to be attacked, and I therefore have a right to defend myself with an appropriate amount of force. In that case it might be something as simple as pushing the person away to create distance, backing away, and so on. If there was reason to believe the individual was armed, it might mean pulling a weapon. Depends on the situation, and each one is unique.
That's not what happened to Mr. Smart. As it turns out, some guy many feet away from him said something stupid, like "you're a piece of crap," and Mr. Smart made the decision to get up and attack the man. Very poor decision making by both men. The first man, IMO, does not have the right to call Mr. Smart anything offensive. I happen to believe that there should be no place in sports for a fan close to a player to call him "crap" or anything offensive like that. Cheer or don't cheer. Jeer even. But personal insults from up close should warrant an escort out of the stadium. Why do we make exceptions for such foul behavior because the person has paid money for a ticket. Mr. Smart, for his part, decided to assault a man for being called a piece of crap. Very poor decision, and very poor control of his emotions. But this is not the first time he's shown that propensity. He was losing control some other game when he was wandering around the stadium or something.
Both not okay, but please don't try to let Mr. Smart off the hook by suggesting that the other guy was "in his face." He was not. He wasn't even close to being in Smart's face. Smart decided that he was going to go all bad-ass on the guy. Smart will do it again at some point. He has an anger/emotion control issue, and my many years on the planet have taught me that those don't go away, but only re-manifest themselves when new triggers occur, which they will.
Punishments seem about right to me - Smart 3 game ban, Fan gone for year. Smart should be told that another push and he's gone for good. Fan should be told another, single insulting comment and he can be a Longhorn fan.
And to the members of the black community who were quick to allege that the idiot fan called Smart a n!gger, shame on you for attempting to foment discord and curry attention. Race relations in this country are bad enough - everybody needs to work on not jumping to conclusions when race issues spring up, because conclusions jumped to are usually wrong.