Reverse the players and what would the response and actions be? What if a union worker wore an Obama T-Shirt to a Bush or in this case a republican rally of some sort?
I agree this guy will likely win in the end but he made a choice based on politics and he'll just have to see it through now that he's down that road a bit. If you wear a Black Sabbath T-Shirt to a Jerry Falwell Revival (I know he's dead) you have no expectation of being ignored!
Something about that thought does appeal to me!