What makes the original comment legally problematic (IMHO), is that it is expected and intended to have a chilling effect pre-publication. Effectively, it would end internet anonymity.
It's not necessarily unconstitutional. I would have made the argument if I thought so. The point is rather that history teaches us that close control of publications is a terrible mistake.
The original comment wants to make sure that there is always someone who can be sued/punished, with obvious consequences for regime critics, whistleblowers, and the like.