Most venues put warnings on the back of the ticket about how they can't be held responsible for batted balls, wayward pucks, etc. Why not just add on that they can't be held responsible for you deciding to act like an ******* and getting put in your place, be it by another fan or competitor? Smart is gonna get the weight of the flack on this issue, but if that fan did use a racial slur, how can you fault Smart for shoving him? As another poster mentioned, if this happened out on the street, Smart would carry no blame in this instance. Purchase of a ticket does not grant you free reign and protection from retribution.
If you decide to shove a Klan member at a rally, you will be charged with assault. So, your assertion is unfounded.