It's not required, just part of the default procedure. An author that submits a #FEP can just as well choose to collect feedback in other channels, update insights on the tracking issue, and improve the text with PR's without hitting up the #SocialHub forum.
A decentralized ecosystem will evolve in many different ways. The bottom-up Standards Process needs good procedures and see them popularized, so they become natural. There's much to improve, both in FEP Process and also #W3C.