If you can find a remotely credible source that credits Westboro Baptist Church with even a hundred members, you’re a more energetic or skilled researcher than I am. When Pastor Phelps describes his congregation as family, he’s not really stretching the truth.
The lawyer arguing before the Supreme Court, Margie Phelps, is Fred’s daughter, hardly a hired gun. Indeed, she’s been an active contributor at a large number of the Westboro protests against sin. (In most movements I know about, there’s a sharper division of labor between advocates in the courts and activists in the streets.)
Either Phelps would readily describe their views as well outside the mainstream of American life, shared by very few Americans. (Don’t take my word for it; read an interview with Margie.)
No doubt, it’s not hard to find sin in America (although we often differ on definitions: splitting infinitives? cheese with seafood?). Westboro protests at servicemen’s funerals, the Holocaust museum, and Catholic colleges–among other sites, not because they are the most sinful, but because they will be the most visible.
Dahlia Lithwick offers an analysis of the court case at Slate. She says constitutional law on these matters is unambiguous (the first amendment protects hateful speech), and wonders why the Court took the case. She speculates the some of the justices wanted to condemn the protesters.
So, in comments, Lukas asks whether disruption really works? Would you know about the Westboro church without it?
Maryann Barakso wonders whether there is any long-lasting benefits for the crusaders against sin. Certainly, the Westboro campaigns probably don’t help the cause of a much larger number of people who advance a fundamentalist interpretation of the Bible. They’re not the people you want carrying your cause.
Deana Rohlinger offers another answer: witnessing and facing opposition and confrontation is a testing by fire that solidifies the faith of the few, their identities as Westboro fundamentalists, and their commitment to the cause.
Note that other marginal causes employ similar tactics. Here are a couple of examples from the acolytes of Lyndon Larouche.
Such efforts aren’t about convincing people of the merits of your claim. Rather, it’s about getting attention through/and provoking confrontation.