Possible tangent, but one problem I see with any of the moderation strategies is that the definition of the word "harassment" is far too subjective.
As far as I understand, something is harassment if the reader feels harassed by it. A speaker has no control over what the reader feels, and therefore cannot with any certainty avoid "harassing" anyone who could possibly see the message.
This leads to a strong chilling effect on speech, which is easy to see in practice in any space with a strict "no harassment" policy. Again, you might be okay with that, but it's hardly an open marketplace of ideas.
If we're going to set rules, they need to be more prescriptive and less reactive.