People who refuse KYC think that playing gambling doesn't need to submit their personal documents, especially those who don't use big money. And thinking is normal because they are not the big gambler type and only use gambling for fun. And those who use gambling for more than just fun can accept KYC and enter into it to get something out of the casino. After all, they believe the casino can keep the personal documents well.
Gamblers who stake hugely should prefer casinos who are reliable and those reliable casinos always ask for KYC. They should prefer them because of their trust gained over the years. For example stake has been around for a longtime and will not want their reputation to go under the ground so what you know is if you play with them and win your money is guarantee that you will get. Therefore if you know a casino has a very good trust rating, you just go ahead with the KYC so that you can easily withdraw whatever winning you have at the time you request for it and not to use casinos that are not asking for KYC yet you won't be able to withdraw your winning.