I was in Washington, D.C. this past October for the annual Values Voter Summit. When I pulled up to the host hotel, I was dumbstruck to find a group of atheists staked out at the front entrance, mocking the summit’s preponderantly Christian attendees. Such in-your-face confrontations by atheists are becoming increasingly common. In fact, atheist activists bear many of the characteristics generally associated with a “hate group,” as defined by the Southern Poverty Law Center, the accepted authority on the subject. The Center says a hate group is “an organized group or movement that advocates and practices hatred, hostitility or...