There is also a psychological aspect of account deletion: Deleting an account can provide closure and make it clear to yourself and others that you distance yourself from a site - even if your old comments stay up.

By preventing users from closing accounts, HN is deliberately blurring the lines of who is still active on the platform and who isn't.

Lastly, if it really turns out there is a reliable method to associate HN accounts with a real-world identity, HN will get in trouble with the GDPR.

Really guys, leave the comments up if you have to, but give people a way to remove their account from it.