KYC is like safety measurement of the casino to those people who make a suspicious activity with their account so the casino will make sure that they are a legitimate player and doesn't abuse at all the current system of the casino, also to make sure the transactions are all in a legal way, people tend to don't want to have KYC well yes because they want to make sure themselves are still anonymous so they keep looking for a casino that doesn't require a KYC, but in the casino side they just was not to protect their business to to prevent illegal actions.
Even though some people are still not ready to accept it, it's a known fact that KYC verification isn't something imposed by the will of casinos because they want to do it but it is a part of the laws imposed on them based on which jurisdictions they are operating in and any casino that wants to operate within those regions and wants to acquire a license for it will be forced to add this rule for their customers, otherwise, they wouldn't be allowed to operate.
I still remember there were no such rules when cryptocurrency casinos were launched initially, a gambler could deposit and withdraw large amounts of Bitcoin and other cryptocurrencies without any problems, the price of Bitcoin wasn't as high as it is today back then, but it was already quite popular.
Later on, the authorities started regulating the casinos, and casinos started asking for KYC verification from their customers.