Basically, i believe this sign alludes to the group of known as the Freedom From Religion Foundation, who are known as the freethinkers. In the case of Hein v. FFRF, they sued the government for funding religious social services. This is one of over 100 suits they have lobbied to stop religion from being allowed in public places. I am a Christian, and while i dont want to ever be one to push my views on anyone else, it is difficult to see them pushed on me. As a lawyer i understand separation of church/state, however, A) this country has foundation of religious belief, B)prayer in public places and funding of religious services (that provide the exact same service as secular groups of the like) should be allowed as a matter of freedom. Thats what the courts held in this landmark case, more for upholding taxpayer standing than anything, but basically, these are people who fight to remove religion from everything in the world, thus, the work of satan in a christianity point of view.