The GDPR protects the data of users on your systems, you must for example remove all the data of users if asked and you must do a lot of stuffs more of course(thank GDPR). But when you are an enterprise, the data of your employee might be owned by the company, and even if the employee left the company, you could need some of his email, files in his home, addresses of his customers, his agendas…
Actually when you delete a user in the server-manager, you remove all the data owned by this user.
Hence we could have two ways to protect the data of a possible erasure, one conservative, one active
We could only state in the documentation, if you want to keep the data of a user, please deactivate the account in the server-manager…simple and efficient, but I must add too the @giacomo’s sentence : Less code, less bug
We could make a global property in the esmith database and do not remove the data when the event user-delete is launched. This way might be better for me because in a real environment, you are several admin and an error could occur…damn I removed the user. Of course backup are for this situation, restore data removed.