It's good to see that someone else understands exactly what these vermin are.
Fred Phelps himself is a disbarred lawyer. He would offer a smaller settlement amount to go away and not press litigation in many cases.
The reason they chose Homosexuals to protest is that there is a scriptural basis to be against them and that can be protected on Freedom of Religion grounds in their speech against them. They are vile and provacative in the hope that someone will offer minor but actionable offense against them or they can sue the locality for not protecting them.
Homosexuals are not known particularly for violence. You would never see these assholes with signs that say, "God Hates The Hells Angels", or "God hates the Crips". .