I have privacy concerns please check again.
This must be possible when I search other threads their account is deleted and their post appear under "Anonymous".
Posting anonymously is an old feature of the forum that is now removed. Their account is not deleted but they just use anonymous posting feature before that’s why their account is displayed anonymous until now.
Just delete all your post in the forum and report to moderators all the thread or post that can’t be deleted. Just include the reason and I’m sure it will be deleted.