Anyone here ever coded such app? This is not about privacy but ALSO sanity for the devs : we do not delete stuff on the database unless necessary. Deleting entries can create many bugs and headaches.

Also for me it makes sense to keep message as there are part of a thread so the conversation wouldn’t make sense anymore. Keeping message of a deleted user is a feature : I don’t mind my message answering someone else being kept and showed as originated from a deleted user. To do that, as any message NEEDS a parent user, you also need the user line to be kept in the database for consistency. You just mark it as deleted and maybe clear the password/login so is cannot be accessed anymore.

That’s may be not THE reason but it is very common to do that in application. We delete only the private information of a user upon request but not the user itself to avoid blasting the whole DB.