OPs point is that we shouldn't allow "individual services get to decide requirements for their users". If the spec requires being implemented in a way that allows that, it's a user-hostile spec.
That wasn't their point and is orthogonal to their misunderstanding of the GitHub issue where, again, no threat is being made.
But in any case services do get to decide, because the service runs on someone else's computer, not yours. You get to decide what happens on your computer, they get to decide what happens on theirs.