It does seem logical to think like this at first and I would agree with you, but it did happen. For example, you have this number of YT channels that would often talk about atheism starting talking about how feminist women were, complaining about LGBT people and such. Maybe because they got too familiar with libertarian ideals and ended up going conservative.

I am just pointing out that this is something that exists and it is something talked about. I am an atheist and leftist but I think it is a mistake to automatically label atheism as something strictly progressive as if your way of engaging with atheism is through hate and without empathy one can easily go through a dangerous path.