A lot of spam is posted by unregistered users. They only have accounts on one site, and their only contribution is a spam or troll post. In my opinion, such users are not worth keeping. How about if an unregistered user's first contribution ever gets deleted as spam or offensive, the user just gets automatically deleted. This is one of such users.
Here is an example of one of such users that should be deleted/destroyed https://askubuntu.com/users/1042335/william. If you are a moderator reading this, please delete that user.