So in other words, BWF (referee) doesn't want to have anything to do with any umpire mistakes and going to let the umpires making fool of themselves on TV. To some extent, badminton sport professionalism.
I'm not sure that's exactly what happened, but your point could still be valid. It did appear that the line judge signalled 'unsighted', but the umpire still treated the situation as a challenge by the Koreans. This would make sense if the umpire had made the line call himself, which I believe he can, just as he can still overrule calls by line judges; however, I did not hear the word 'correction'. Nor did the umpire say the words Kim So Yeong is challenging the call. The shot was called "out". However, the umpire did say both Challenge unsuccessful and One challenge remaining. If this were an invocation of HawkEye due to an unsighted line judge, neither of these things should have happened. As I say, though, even if the umpire in fact made two mistakes - 1) subtracting a point that had already been earned and 2) penalizing one team for losing a challenge that the court officials should have been taking responsibility for themselves - then your point would still be valid because the root situation of having the confluence of an available IRS system and an unsighted line judge is the 'new situation' that your are referring to, at least if I understand you correctly.
He might have told them if he saw that there was a mistake but his job is not to follow the score but to make sure that the decisions of the umpires follow the rules. The question was what is the score and than it IS "the point of fact", but it might be slightly different question that than becomes a "point of law", like "it was 5:3 before the challenge, what is the score now"...
It is not necessary that there were two mistakes. If players wanted the challenge, technically he can make the challenge as player's challenge and not umpire's...
That would be at the very least, a cynical interpretation of the rules. However, I believe it would simply be an incorrect interpretation. Regulation 1.1 says 'On a court where an Instant Review System is in operation a player/pair may challenge a Line Judge’s call, or the overrule call of an Umpire.' If the line judge was indeed unsighted and the umpire hadn't yet made a call, the umpire needs to reject the call for a challenge. The rule does not say that a player or pair may 'call for a review if the Line Judge is unsighted and the Umpire is not able to make a decision.' Only the umpire can do that. My guess is that either the umpire said 'out' and it was inaudible on the video, or the umpire made a mistake. Either way, what possessed him to subtract a point if, with an unsighted line judge, he was the only one who could make a call that could have bumped up the score? As you already pointed out, the umpires are not supposed to add to the score unless they have verified there has been no challenge and you'd think that would go double for a line call that the umpire has to make himself. How could he increase the score if he hasn't decided whether the shuttle is in or out?
I would not draw the line of what constitutes judgement vs laws there, but if BWF does, then by definition they are right. If the referee had opened the view of recent changes to the score on his tablet, and seen that a score entry had been undone, just after the IRS button was pressed, then I have no doubt that the umpire would have fixed the score. To me, the far more likely explanation is that the referee did not have any additional information, and just polled the umpire and service judge for their evaluation.
