There's also a point in cleaning up old accounts in order to protect people's privacy. These might be accounts the user has forgotten or no longer has possibili

There's also a point in cleaning up old accounts in order to protect people's privacy. These might be accounts the user has forgotten or no longer has possibility to access the account (forgotten password). Even though user can't access the account, it might be still accessible to others with malicious intents. Maybe the password was weak, maybe user used the same password in multiple services and it is not publicly available in some datadump.