Message the mods politely. If you made a mistake by posting something against the rules, apologize for that. Usually, mods are happy to unban you in that case.
But some mods become really jaded over time and are mean to users by default. I was moderator of a few mid-sized subreddits for a few years and saw that in action. A common thing I saw is a sort of purity mindset, where a moderator feels like the more people they ban, the better the subreddit becomes. It’s really easy to dehumanize people online - users do it to mods, and mods do it to users. But those bad moderators make users hate mods in general, and the cycle continues.
But some mods become really jaded over time and are mean to users by default. I was moderator of a few mid-sized subreddits for a few years and saw that in action. A common thing I saw is a sort of purity mindset, where a moderator feels like the more people they ban, the better the subreddit becomes. It’s really easy to dehumanize people online - users do it to mods, and mods do it to users. But those bad moderators make users hate mods in general, and the cycle continues.