This is one of your comment from the Github thread,

> ...which affords certain protections under US trademark law and has enabled elementary to prevent people from distributing other items under our brand name—but regardless this issue is in no way a legal threat as much as you want to insinuate...

Honesty, it looks like a legal threat to me despite claiming otherwise given your other comments on the Github thread have been on the legality of your request.

Also, claiming the repo owner has a poor understanding of trademark law when you are not a lawyer reflects poorly on you. If you wanted to change their name to "Unofficial elementaryOS Tweaks" - just ask nicely without getting into legal gobbledygook.