Facebook's oversight board disagrees. They ruled that Trump's ban was "indeterminate and standardless", and that the correct response should be "consistent with the rules that are applied to other users of its platform".
https://www.bbc.com/news/technology-56985583
It's quite obvious he broke no actual rules, but it's interesting that Facebook's oversight board is actually willing to say so. Of course, they nonetheless 'allowed' Facebook to continue the ban.