If you don't want something deleted, you can always keep a copy of it yourself.
Exactly. Which means you can't delete your bathroom video from any networked system. See the Streisand effect.
That is _literaly_ what we already have. If you delete (unpin) content, others are free to keep it (pinned).
The OP was suggesting a way to delete things from other peoples machines.
But the problem is that if you can delete that stuff, someone else can delete stuff that you don't want to be deleted.