You are right, no casino will purposely sell off their customers information to scammers because the casinos are already making too much profit from their company and I don't think their is any amount of money that scammers will offer the casino that will make them sell their customers information. Although, in some situation, it could also be possible that the staffs of the casino could be greedy to the extent that they will steal customers information from the cosino and sell it to scammers just to make extra bucks.
Unless the casino is not actually out there to last for a long time, like they are not seeing enough profit from the business, too much winning, which is already exhausting their reserve on their first time of starting such a thing, if they want to exist, they can warrant the sale of customer information.
Another occasion where the selling of customer information can be done in the casino is by one of the staff members having a side deal with scammers. Without the legal concept of the casino's own, they can pick out a few user details they consider valuable and sell them off in exchange for whatever price they are being offered.
If there casino is running good then for sure that provably they will not do any something illegal since that could provably trigger some hate and their reputation will get ruined with that actions. Then it would lead to a destruction on their casino so provably that actions most like not done by profitable casino just like what we see on trusted casinos in this forum. If we look at the profit gain by successful casino for sure they are more earning a lot of money from their business and for sure selling costumers details will just give them few bucks so they would provably not look at that option since it will just ruin everything what they built for many years. Unless the platform creator is just for identity fishing then story goes different with that situation.
Although we cannot close the possibilities that this actions might really happen that's why its important to select a good casino or a big running casino so that we can avoid those incident since its very dangerous if those scammers will have our private details since they can use it for whatever illegal situations.