PZ Myers is annoyed by the fact that, when it comes core, fundamental, human values, many atheists are as bad as believers, if not outright worse. In the eyes of some, “atheism” means only “lack of god-belief,” which means atheism cannot imply anything more than that, which means that atheism implies some kind of amoral anarchy, above and beyond mere unbelief. So which is it? Does atheism imply nothing more than absence of belief, or does it imply that “they’re right and you’re wrong?” You can’t have it both ways.
In truth, atheism absolutely does have implications beyond mere absence of belief in supernatural father figures. A world without gods to take responsibility for everything is a world where we ourselves are responsible. Atheism implies that we have work to do, morally, socially, and scientifically. And maybe that’s the reason why some unbelievers would rather not acknowledge anything more than just the absence of gods. But I suspect it goes deeper than that. I think what we’re seeing today is the emergence of two broadly-defined tribes within atheism, two different types of atheists, whom I designate as truth-seekers and god-slayers.