Is atheism the only logical conclusion regarding religion?
Theres no arbitrary position that is a logical conclusion or not.
If evidence of religious entities existing is presented that meets the burden of proof, then you should believe those entities exist till new evidence comes along that disproves the old.
The big gap in nearly all theists beliefs is that their standards of evidence are simply inconsistent. I've never, EVER had anyone make an argument about one religion, that couldn't be applied to nearly every other religion. Prove Jehovah doesn't exist! Oh yeah?!? well prove Ganesha doesn't exist! and so on and so forth. The only ones that aren't like this are the ones that get too specific about the nature of their gods and dates and times so their existence can be disproved without absolute knowledge of the universe.
A huge flaw in theists critical thinking is to believe that you should accept something as true until someone has proved it is not.
All you need to have this kind of belief is an immeasurable entity (i.e. make up anything you want and say it can't be measured or tested so you just have to accept it as true, after all you can't disprove it right?), and if you have an old book that claims a bunch of stuff that can't be historically validated it will go along way to backing up the legitimacy. If your god/soul can't be measured or tested in anyway whatsoever, then that's a whole lot of universe that you can hide your belief in.
Religion as a set of preferences or philosophical persuasions is fine, but when it makes claims of
fact about the
nature of reality, then it needs to be
scientifically testable.
So yeah, there may be some gods somewhere, but so far, no evidence in the history of human civilization has come anywhere close to proving gods, as such its reasonable to lack the belief.
A lot of theists put way too much stock about being certain. Theres no need for me to be certain there are no gods in order not to believe in them. All I need, or rather don't need, is to have not seen any evidence worthy of believing such things exist.
200 years ago, it would have been irrational to believe in the existence of quarks, because at the time there was no evidence support such a claim. Now there is evidence, and it is rational to believe in the existence of quarks.
The rationality of a belief does not rely on its relation to absolute truth, but in relation to the assessment of empirical evidence you have been exposed to. Absolute knowledge is pretty much impossible. I could sit around writing down numbers that may be the number of planets in the universe that have life on them, but it would be irrational to believe in any number but the one I can prove.
I believe in what there is sufficient evidence to believe in, at the moment that doesn't include any gods. The fact that I've never met a theist who's tried to persuade me of their beliefs without urging me to avoid critical thinking, and the fact most theists I meet actually don't really care about proving their beliefs to me, or themselves, goes a long way towards me dismissing nearly all theist claims without even hearing them.
But I won't, and I'll still try to judge every new religious claim I hear as if I had never been exposed to all the previous religious fallacies, and if the new claim has evidence that goes even some way to proving its existence, I'll be happy to reassess my beliefs.