I'm pretty sure that this anti-anti protest tactic is in Rules for Radicals and is meant to illicit sympathy for the agenda, and gain acceptance for said agenda from even it's most ardent critics through either their own empathy or the social pressure caused by others being ardently empathetic and supportive.
Fred Phelps is still just a tool, and ɧoɱosɛҳųαƖity is still a psycho-sɛҳuąƖ disorder.