Why can't you just ignore them? Go on any high traffic forum in the world and you'll find racists, sexists, bigots, benefit scroungers, people who joined the "RIP Raoul Moat" facebook page and so on and so on. I'd wager there's even a few living within a half mile radius of yourself, are you going to move to the countryside to ensure you get away from them?
If you feel that strongly perhaps you should become a politician and try to affect change. Refusing to pay a £5 subscription to a forum dedicated to a football team is hardly going to do any good on this subject, is it.