Sort of. While it is true that the only requirement to be an 'atheist' is the rejection of belief in 'god', there are many tangential beliefs to belief or disbelief in 'god'. For example, a theist may or may not believe that prayer works, but an atheist should not, based on the fact that prayer would require someone/thing to pray to. Since atheists don't believe such a being exists, it follows that they cannot believe that praying works. There are other tangential beliefs that aren't as obvious as the example of prayer, which many atheists refuse to acknowledge, but nevertheless, are beliefs that logically follow from the disbelief of atheism.

A suitable metaphor might be that hockey players are just hockey players, but they are also athletes. Basketball players are not hockey players, but they too, are athletes. These kinds of ostensibly simple correlations seem to flummox a lot of people, atheist or otherwise, when they are applied to theistic belief or non-belief. That's because while their theistic belief or non-belief tends to be important to people's conception of themselves, they may have not considered many of the consequences related to belief or non-belief. So when they are put on the spot about an aspect of belief or non-belief that they had not considered, they are apt to fall back on the definition at the top of the belief hierarchy by insisting that their belief or non-belief is only predicated on the belief at the top of their belief or non-belief hierarchy (ie theist or atheist). These inconsistencies are unfortunately the source of much of the animosity between theists and atheists.

For example, atheists are miffed when theists say that their prayers were answered when they recovered from cancer, because the atheists know that many people with cancer prayed and did not recover. Theists will say that’s irrelevant, that only god’s will matters. Likewise, theists are miffed when atheists claim that atheism has none of the 'belief-baggage' of theism, because theists can see quite clearly that there is belief-baggage that comes along with atheism. Atheists will say that’s irrelevant, only the textbook definition of atheism matters. Atheists often insist that their atheism, being a lack of belief, does not fill the same ontological role that theism does for theists, even though in many ways atheism does indeed fill that role.