You and me both know why some casinos does this... right? You mostly find this happening with "new" or "smaller" casinos, because they do not have the funds to pay out huge wins. So they will ask for KYC verification to delay the payment, so that they can get funds to pay it.
They also hope that they can find something in the KYC documents to deny the payout of the win. We are not dealing with people that are selling Bibles here.... some of them have tainted backgrounds and connections with very shady operations.

This is what has been happening all along, where new or smaller casinos are unable to pay out the winnings that gamblers get from gambling. And those casinos will ask gamblers to do KYC to delay their payments.
Everything you say is to reduce the problems that can arise in casinos, but crypto gamblers don't want to do KYC because many crypto gamblers gamble with small amounts of money and don't use crypto to make money. For reasons like this, crypto gamblers don't want to do KYC, especially with the many frauds committed by these shady casinos. Gamblers want to avoid experiencing it.
However, in the future, every gambler who wants to gamble must carry out KYC because there may be many illegal cases occurring, and the government wants to control them. The government does not want to see its regulations misused by irresponsible people, so it tries to apply its regulations to all casinos so that the casinos also apply them to the gamblers in their casinos.