You can save a screenshot discord chat too. There’s nothing wrong with that. If someone published something and you want to save a copy for personal purposes, go ahead.
The difference is in what Discord’s responsibility is.
If Discord claimed to have deleted an account, then they shouldn’t still be publishing a post from a user. Especially if such a post could still be tied back to the historical user id.
I can understand why they’d want to keep the data (sometimes you need to keep an archive of posts for legal reasons - for a limited time). But making an archived post visible to the public is the problem.
An even better analogy would be a mailing list, instead of directly emailing/cc-ing recipients. Definitively not "private messaging".
If I delete my email account, and/or remove it from the list, there's no expectation that my prior emails are deleted for any of the other list subscribers.
The mailing list archive isn't pruned of my account and everything I ever sent will still be visible.
You’d have the right to request removal of your messages from the central mailing list archive (I believe), but not the copies received by the individual mailing list subscribers.
With Discord, all messages are in the “central archive”, there are no individual copies.
The difference is in what Discord’s responsibility is.
If Discord claimed to have deleted an account, then they shouldn’t still be publishing a post from a user. Especially if such a post could still be tied back to the historical user id.
I can understand why they’d want to keep the data (sometimes you need to keep an archive of posts for legal reasons - for a limited time). But making an archived post visible to the public is the problem.