Blackmail you from gambling? is gambling illegal or a crime that you will get blackmailed as long as you are fair and you won it all fair I don't know how you will get blackmailed, I have not read any complaint that high rollers get into that kind of situation and so are traders from exchanges, they are very similar to gambling they have KYC and they also have whales there, but there was no report of getting blackmailed from staff or former staff of exchanges, you are just creating your own ghost.
Maybe you just didn't get his point well or understood what he wanted to convey. Yes, we have not seen or read any blackmail on gambling but it is unlikely that he has already encountered such a scenario, read or heard. Or let's say he's just going to do it in his mind but it's possible to happen. Yes, in other countries gambling is illegal, breaking the law is prohibited, so it is also a crime. Let's go back to what OP said, he just assumes that just in case he is a big roller and after he submits his Identity and KYC verification. We know that not only one staff member works in their support team and they are not the same. What if the OP thought that there was a reprimand staff at a crypto gambling site and they stole his info. and data and use it against him just like blackmail. Of course, you will know his full name, birthday, and address.