Seems a few have used to the term, probably to keep it simple for boneheaded theists. Although I wish these people wouldn't, it's pandering to theists. It's simple, 'atheist' does not believe in God. 'anti-theist' believes there is no God. I don't expect people to use the terms 100% correctly 100% of the time. So a few get it wrong, but then the majority of those professing to be christians don't live by christian ideals either, so I'll trade you that one.