/r/atheism bans you based on what you say in other subreddits, despite it not breaking any rules. Unless you're a liberal that is, then they don't care.
I made a few conservative posts on /r/atheism. Next thing I know I'm banned. When asked why, the mods of /r/atheism send me a quote of something I said in a different subreddit. I did not break a single rule in /r/atheism and what I said in another thread had nothing to do with /r/atheism.
Next I'm muted so I can't talk to them. So I wait 72 hours.
I ask then to be unbanned. He sends me a quote of the title of screenshots I took of when I was banned. An image submission I had submitted to /r/oppression.
I ask what rule was broken. He says it was already provided. This is false. The only quote provided to me was something I said in a different subreddit.
Muted once again.
In summary. If you aren't liberal enough, you will be banned from /r/atheism and then they will make up reasons why you were banned. When asked, you'll just be muted.