Mmm. This is broadly the same story as the other thread, which I checked again:
Note that also led to a fatal error on startup.
In broadest sense, there's little point in "checking" if you are not going to do something based on the result of the checks. In this case it appears the ownership/permissions are considered an issue that also means a fatal startup error. Probably @DavidTurner or someone else will have to answer to clear up the doubt. Would it be a bug that this completely prevents startup? IMO yes, but without too much conviction. I do agree the way it fails, like the path.repo case, is not helpful or user-friendly from an admin perspective. And I also agree the set of "checks", and any consequences, should remain as consistent as possible through 8.x to 8.y upgrades, but it feels like that train has already left the station.