Gandalf the Gorsed

I love eating lemons and limes but I try not to do it too often. Definitely not good for my teeth.

Atheism isn’t really a belief system by itself. It can refer to a lot of things, including positive atheism (the claim that there is not/cannot be a god/supernatural entity), negative atheism (the lack of belief in a deity due to lack of evidence), the absence of religion and many other things. Militant atheism, on the other hand, definitely counts and is susceptible to all the failings you mentioned.