Atheists turning to cult behaviour?

[Mister Agenda]

Yeah. No one can just have "Atheism".

So true it doesn't even require capitalization.

Each has extensions.

Now you're getting into a tricky area. Extensions of atheism, or extensions of atheists?

There are scientific atheists, rational atheists but also fascist atheists, racist atheists.

Yep. But not scientific atheism, rational atheism, fascist atheism, or racist atheism.

But the problem I feel is the generic idea of atheism which everyone claims to identify with is pure non belief.

Yet you seem to acknowledge that it is factually the case that atheism is not believing in real supernatural deities, so it's unclear why this is a problem for you.

Yet, the extensions are inevitable.

None of what you described is an extension of atheism. Christianity is not an 'extension' of theism, it's a theistic religion. Black clothes are not an 'extension' of blackness, they're just clothes that are black. Theism is ALSO nothing more than believing that at least one supernatural deity is real and doesn't say anything at all about a person's morality or political stances or, really, much of anything at all. You learn a LOT more about a theist when you learn what ELSE they are. In a more reasonable world, people would no more assume they know your other opinions if they know you're an atheist than they would assume they know all about you if all they know is that you're a theist. But that's not the world we live in. 'Atheist' is a meaningful identity precisely because SO many people don't understand that it's no more than it is. Even other atheists are often confused about it.

Why not append the emptiness of pure atheism into something meaningful?

Everybody who is an atheist...and I mean EVERYBODY...does. So do theists. Pure theism is nearly meaning-free, and there's nothing wrong with that. It's not supposed to carry loads of meaning. Why should atheism be different in that regard?

But when an atheist indulges in bad behavior in the name of freedom, and when others say it's not my problem "I'm just a non believer". How do you deal with that?

Rather than holding anyone who happens to agree with that person on one single thing responsible, I address the person behaving badly myself.

I'm clueless too as to what the solution is.

To humans sometimes being mean? There isn't one that's ethical to impose.