The people have already made their choice, and it's clear they prefer a KYC casino over a non-KYC casino. I believe it's more appropriate to refer to it as 'decentralized gambling' because some casinos claim to be non-KYC but are still regulated. It's important to question the longevity of such claims. When a casino is regulated, it's obligated to adhere to the implementing rules set by regulators, including KYC compliance. So, it's wise not to trust those that claim to be non-KYC casinos.
It's not possible to get a clear statistics on if people actually prefer KYC required casino over no KYC required casino, personally I have no problem with kyc required casino platform or no KYC. But there are factors that should be considered before choosing.
Anonymity: many Crypto-currency enthusiast are strong on having their identity secured and protected so they would tilt towards the no KYC required exchange but if the security of their identity can be assured then I see no problem with undergoing KYC requirements.
I think it's the responsibility of a casino to comply with secrecy laws, much like banks have their 'bank secrecy laws' that penalize them if they leak their clients' personal records. Sensitive information should only be transferred between government agencies, and all of them are governed by such laws as well.
The individuals: some individuals can have criminal history and would definitely not go for KYC required process.
Obviously, they would stay away from casinos that require KYC verification, as that would put them at risk of getting easily caught.