Most of the online gambling website doesn't require this KYC on their websites. That might be a big deal for a lot of users since they are risking their personal details so a website but there are also users who don't really care about their personal information since most of it is already online anyway. Probably KYC is use for user control and also most of the time for security of the website since it involve a lot of money in a gambling website it is just normal for them to take counter measures especially for a lot of hackers out their.
Personal I wouldn't do KYC for any gambling website because i don't really want to risk my personal information for a shady websites but i could do it for some gambling websites that is already trusted that is in the listed. But we love gambling for even for a lot of user kyc will not matter at all.