WBC is the real life version of an unintentional troll. These guys aren't trying to stir up trouble for the hell of it. They really believe what they preach. Which is sickening. They may call themselves Christians, but even as an atheist, I can tell these guys are some sort of hate-cult. Although I bet we all wish that we could yell at these guys face to face and tell them what kind of scum they are, it wouldn't do squat. They would just feel that they're being "persecuted" for their beliefs (which I guess they are, but with good reason).
I can see only a couple options to getting rid of these guys. First way is to just wipe them all out, forcibly. It would work, but even I hesitate to think that its really the right or necessary way. Second way, ignore them. The only thing is, these guys are so nuts they'll just keep doing what they're doing. Its not really getting rid of these people, just tolerating them and hope that they'll "die out" due to disinterest in them. Finally, my favorite way, counter-troll. Find some way to get under their skin and exploit it for all its worth. Counter protest them, perform these "sins" in front of them (they get pissed, people get happy, double-score!), protest the funeral's of their members (distasteful and lowers us down to their level, but still it would give them some of their own medicine), and calmly mess with them by "not-understanding" them or comparing them to someone they hate ("You guys are against fags too? Aw man, you should come to my neo-Nazi rally some time, you'll fit right in!").