The WBC is a "for profit" (not "for prophet") organization.
They do it for the money. Their intent is to offend, get assaulted or interfered with so that they can sue. They are a litigation business. These people are opportunists, not religious zealots and their goal is the settlements or judgments to be awarded after their provocations.
I read that they are basically a family group (not a public church congregation) and that the family includes 12 lawyers, which would explain a lot. If I can find that article, I will post a link.