1. KYC requirements reduce money laundering.
2. KYC requirements reduce under age gambling.
3. KYC requirements increase the possibility to hold people to account for their actions. (Exploiting casino systems)
4. KYC requirement reduce scamming
5. KYC requirements can be used to restore accounts after it has been hacked. (Using the documents that were used by the original owner)
6. KYC requirements adhere to government regulations and legitimize a casino.
7. KYC requirements can be used to reduce gambling addiction. (Identifying people that self-excluded or people trying to create new accounts)
8. KYC requirements can be used to enforce regional gambling restrictions.
Sorry' KYC doesn't diminish all of these pitfalls you have listed above, don't make it seem as if with KYC all the enlisted are solved, because it's not.
1: money laundering racketeering mostly use kyc requirements gambling sites using forged documents to pass kyc. Because if the believe that kyc gambling sites reduces money laundry activities money launderers tend to use them more often as it will be less suspicious than when using a non kyc site.
2. This is a falsehood as underage can use the documents of parents or older siblings to pass the KYC process without the gambling site suspecting it.
I can keep disputing your claims on and on one after another but need not be since you're playing the devil's advocate. We are all gamblers and we know what's up on this debate.