Ever hear of the "two wrongs don't make a right?" You cannot respond to an idiot by being an idiot and think that your act of idiocy is acceptable while theirs is not because they did it first. If Smart had turned his back to the situation and then reported the conversation to the media afterwards, Texas Tech would likely review the situation and determine if action is warranted and Okie State has the ball down one or two with 6 seconds left to try to tie or win.
Instead he reacted to a jerk by being an even bigger jerk and screwed both himself and his team. As I said, for the purposes of justifying Smart's actions, it does not matter what the guy said because there is ZERO things he could have possibly said that justify what Smart did. The only thing I would think would be justification enough is if Smart saw this fan physically assaulting a member of Smart's family. Other than that, Smart has to shut his mouth, turn around and walk back out on the court.