Seems like both sides are a bit full of themselves. Since the FSP does not own Roger's and would presumably NOT involve the Police (this could well be a false assumption) how would they enforce the ban? Use of force? Sure they could get some to shun him but I have the idea that those that would shun are people he doesn't care to be with anyway.
As for the "People drive drunk at Porcfest all the time" defense. FUCK YOU asshole. Sounds like a good reason to NOT attend. As someone who was an EMT for years let me tell you I am not willing to play Russian Roulette with my life just because some asshole thinks they still have the coordination to operate a motor vehicle while drunk or high. This is from someone that is for full de-crim. Your driving should have been seen as an act of aggression and you should have been defended against with extreme prejudice.