Stablecoins are also cryptocurrencies and can be used in both casinos that mandate KYC and those that does not. You should not make it look like stablecoins pro KYC while the others are not because there is no connection between stablecoins and regulation of casinos since they are just like every other means of deposit/withdrawal. Now that I have made this clarification, the answer to your question is a no. Even casino that allow deposits via Bitcoin, they can decide to make KYC compulsory or optional. It is up to the casino to decide how they want to run their business.