I got a similar ban from that community after the moderator started spouting conspiracy theories at me and I didn't agree with them. I noticed they removed most of my comments in that thread, but not all of them... Not sure if it was accidental, but the ones with non-negative karma were the ones that got removed.

This is also how I discovered a moderator that bans you from their community effectively prevents you from deleting any of your posts in it, which makes me feel... Uncertain about the ML mods having such control over the stuff its users post.