Just as there are phony Preachers who are really businessmen tapping into a market, could there also be phony atheists and antitheists doing the same?
Possibly - but how could you ever tell?
If, for example, there was a devout Christian who pretended to be an atheist in order to stage a later dramatic conversion to Christianity, what would give them away as being a fake atheist? Plus, if they were doing this, wouldn't it mean bearing false witness or something?