Either folks are misinterpreting the word "atheist" or they're lumping in agnostics as well.

It doesn't matter: scientific fact has refuted the Bible, completely. The Bible has been proved wrong over and over again, not only on science and fact and logic and history, but also on morality (read Joshua if you doubt it). You don't need a poll to tell you the Biblical God has no basis in reality, anymore than you need a poll to tell you what two plus two equals.