They fake being a religion to make money in 3 easy steps:
1. They know their first amendment rights, their protesting laws like the back of their hand. They push and push and push the grieving, the religious, other support groups until one of them attack, harass, or threaten.
2. It is at this point that Westboro Baptist Church moves to litigation in civil court and hence the money making. They press people at their most emotional states, using an emotional topic "religion", and almost always get an emotional reaction.
3. Rinse, Repeat. This is the lowest form of hate and greed combined. AKA Profit.
They pay no taxes as they basically bully people who already had a great loss out of money. Sounds like a gang or other organized crime like the mob to me.