1) it's a response to a user's request, i.e., not initiated by the repo author
2) it depends on consensus of the user.
3) it's not automated (most of the items from the policy are related to automation).
4) the repo author has no obligation whatsoever of maintaining the project. He is not paid or forced to do it.
5) if the user really wants to apply this change or disagrees with this practice, he/she can always fork it.
That said, I understand that it may still not feel "fair" compared to other projects that don't follow this practice. Or the feeling of "wanting to help but you're asked to do some things first".
Companies already do that to accept your pull requests though [0], which takes way longer than giving a star - and I didn't see a complaint about it on HN