It seems like they didn't even consider any of the real issues. Things like deleted messages appearing in requests for your data, leaving a chat (or deleting your account while you are in a chat) with a deleted user not deleting the messages and uploads even though nobody is supposed to be able to re-join it, people getting banned for using scripts to mass-delete their own posts and in some cases getting banned for manually deleting their own posts "too fast", "right to be forgotten" requests being ignored, etc.