huh?

I'm certain I'm missing something; I just don't know what. Perhaps you can help me out. In the NYTimes review of Religulous, the new movie from Bill Maher and Larry Charles that attempts to unite and call to action America's atheists and agnostics, I read the following:

Of the 16 percent who told Pew researchers they were [religiously] unaffiliated, only 4 percent said they were atheistic or agnostic; the others said they were “nothing in particular.” And even among disbelievers, 21 percent of atheists and 55 percent of agnostics said they believed in God[!]. (my emphases)

Clearly I've misunderstood what I thought was one of atheism's central atheological tenets . . .

[HT: Chris Brady]