I think the part you're missing here is that the author here is under no requirement to accept changes to their project and everyone else is welcome to fork it if they disagree with choices made by the author.

The author did not in fact, make the project worse, all they did was not accept a change, and that is entirely different than making it worse.

Even those who stood to benefit from the change have not received a degraded experience in comparison to the current state of affairs, but the same experience as the current state of affairs, since no change occurred. It is truly within the author's rights to do this, in any case.

One should avoid a sense of entitlement to additional and ever-increasing quantities of free work when free work has already been done.