WBC is a bunch of attention whore sudo-holyrollers that have figured out that if they do things that makes people mad, they get recognition. If you seriously think for a second that they're legitimately doing this in the name of god, then you've proven as to why their name is so infamous.
They do something atrocious (I.E. picket a funeral, make a "god hates cigarettes" website), people get mad and start posting angry things on blogs, forums and whatnot and they get infamy + media attention.
It's simple.