I'm stating the obvious here, but it's of course not about the rules. The rules are there simply as a pretext for the ban. They don't care to inform you which rules you broke because you either didn't break them in any meaningful way, or they just don't want to waste the time doing so. They have no intention of doing a temporary ban or correcting you in case you've simply made a mistake. They want you off the platform. As Hillary put it, we're deplorable and irredeemable. Everyone forgets she said the irredeemable part. Once they've pegged you as such, no discussion or rehabilitation can take place. They will remove you in the easiest way for them, in the most costly way to you (remember how CloudFlare dropped The Daily Stormer in the middle of a DDOS?), and they take pleasure in inflicting pain on you. It used to be that reddit would shadowban accounts. The user was not notified of the shadowban and any comments or posts the user made were not visible to others, but would appear visible to himself. A shadowbanned user might continue to post for days, weeks, and possibly even months, thinking that his post were so worthless that no one engaged with them. It was done to inflict and maximize emotional pain on the shadowbanned user.

My reddit account is 11 years old. Back when I created it reddit was in its libertarian Ron Paul phase. The site was explicitly pro-free speech.