You were banned for support of what Reddit (and maybe US law) considers a terrorist organization. There is zero flexibility here and they probably reported you to the government as well.
As far as I know only material support of designated orgs is a crime but they have been pushing increasingly for social media to clamp down on “misinformation” and most social media has been happy to oblige as advertisers don’t like perceived extremism either.
I said it some months back but I’ll repeat that with the cracks of empire showing they’re going to clamp down much harder on any dissent.