Realization comes late after those people got scam. Most of them do background checking after they got compromised, if they just do their research before participating for sure they can avoid this problem. To many people could give their insights if they just ask since for sure for so many gamblers here staying in this forum for sure they will share their experience and feedback to the casino ask.
Also maybe he's just afraid to get scam for second time around since if the casino is proven scam there's no use for providing his KYC details since he might get more bigger problem with that.
Gamblers and every single market participant needs to learn that we do not enjoy the same kind of protections the fiat system gives us, if this was a problem with a fiat casino the OP could just open a dispute with their bank and they may be able to recover their money this way, but on this market we are our own banks and this signifies we need to protect ourselves as much as we can, and doing our due diligence before gambling at a new casino seems like one of the most basic things we could do to achieve this.
That is the exact point that most cryptocurrency gamblers avoid before joining a platform, people tend to get excited when they see very high bonuses being given by new platforms and forget that they might be a trap for them and what if they lose their money only to get that bonus, I know that you can always lose in gambling even if you are using a trusted platform, but that doesn't mean that you should go ahead and choose a platform you've never heard of.
A trusted platform will have a presence almost everywhere and they can be reached out easily and even if you face an issue, you will be able to get it solved because they won't just ignore you and take your money which might happen if you are using a new and untrustworthy platform.