Hi. I’m a moderator for other subreddits. I can explain what *might* have happened. As a mod, especially on big subreddits, and even more ones that gets polarized, it can be exhausting. They probably had conservatives calling them names in their inbox. They can get tired and frustrated of all the people spamming things in the subreddit. They got tired of you trying to argue against them. You were mostly at the wrong place at the wrong time. Was it fair? No really, it was pretty harsh. Was it understandable? Absolutely.

In the last month, it got overrun by Incels

That’s not how shadowban works. Shadowban is that you can comment. However, other people won’t see your comments, and you be left wondering why you don’t have replies or at least people upvoting/downvoting you. So either you were banned from that subreddit, in which case you would have received something telling you that you were, or Reddit just wasn’t working.