He divides fan bases and inserts politics into something that's meant to be a temporary escape from it. (If you don't believe me, why is there a separate thread for politics here and the mods will generally shut down any sort of political debate that arises in threads meant for football discussion?). And that's the case even if he lives up to a promise not to do it, as reporters will make it about politics anyway. It's even worse in Miami with the whole Castro t-shirt thing, which is why it isn't happening here anyway.
