How you differentiate, I dunno. That's the problem.
Would you argue that a person accused of crime X should be told nothing about the nature of their transgression? To me it sounds very problematic.
I have been banned from a couple of forums/groups and I really have no clue about what might be the reasons but I don't insist there were none.
Why can't Facebook just have a hotline/chat that can verify a user's identity and tell them more, preferrable in less than 5 months of spamming their email?
And in the case of a permanent ban the user should at least be able to download all their account data; this feature is already implemented for compliance with GDPR anyway and the online platform wouldn't lose anything by at least not making pictures etc. inaccessible forever.
In short, you are proposing that we penalize good actors for actions of bad actors for no other reason that it creates inconvenience for a platform. That is not acceptable.