I mean KYC is pretty basic thing. They need to know who you are legally by gambling and casino regulations based on the geographical laws in which it resides. I guess for a casino they see that you can't pass the KYC requirement to claim the winnings therefore the transaction is void and the house wins. IF someone was to argue that in a court of law and they can't even answer some simple KYC questions I think they have some other problems that they make for them selves there. The casino knows this and thats why they get away with it.
Do you think people won't give their KYC when they hit max win?
They will verify their accounts as fast as possible, even the casino ask documents that they didn't have yet, they will create it in order to withdraw their winnings. But, what if the casinos ask ridiculous or almost impossible KYC like
street selfie?
KYC isn't the problem, the casino is.