I believe the reason that he got skewered was because it was Red not gained from information from the game board, whereas their red with Krauss being dead can be proven, its just that Natsuhi would never challenge it.
The line where Uraume says that Sukuna lost due to being a fully fleshed curse isnt even correct at all too, it was because he was an incarnation. Do they really not have anyone else to do the series or is it just a contract?
Chapter 108 "
In Tibetan Buddhism, there are 108 delusions, and spiritual teachings in other eastern religions also reflect the number, with Hindu deities being given 108 names and Jainists believing in 108 virtues. These teachings serve to remind of us of our connection to the world around us."