There is a lot of spam on reddit that mods choose not to address. Political subs with a few accounts whitelisted for thread submission, posting the same agitprop, dateless twitter screenshots talking about how shitty Corp X or Politician Y is. Comment bots that will have entire conversations with each other with meme banter, building upvotes.

Then there are the less malicious ones, like the quote bots on Lord of the Rings subs.

If this person was banned for having a template message about migrating to a different site, it shows a priority by reddit admins to eliminate message spreading about a competitor. It's trash.