I feel you. Thanks for the comment. "Right to be Forgotten" was the phrase I needed to see for that to click.

I think your analogy is off the mark only in that, in the situation you describe in the lemmy platform, the teacher's video disappears, but everyone can still see that they posted something.

I do hope that in time, lemmy devs remove the username next to deleted posts.

As I said to OP in another comment, lemmy gets a lot right when it comes to privacy, and much more right than most social media platforms. For me, I won't let perfect be the enemy of good.