For archival purposes for future searches on this subject, I have come
across a document entitled "ULTALIGHT VEHICLES: ACCESS AND THE
GENERAL AVIATION AIRPORT ENVIRONMENT" by Bob Moorman (no date).

This handbook is a good reference for the steps to be taken to file
both an informal and formal complaint with the FAA with respect to
access denial and unjustly discriminatory rules not in compliance with
Airport Sponsor Assurances (applicable for any FAR Part 103 defined
aviation activity to include gliders and ultralights).