You are talking about people who have a pronounced gambling addiction and they visit casinos not for gambling or pleasure they have a compulsive and unhealthy desire to beat the casino. We all understand that this can happen only by chance and judging by the theory of probability of such an event is unlikely, but gambling addicts do not understand this and with manic passion trying to win a large sum. Such people need urgent medical and psychological help otherwise they may suffer from their desires.
Unfortunately there is still a huge stigma against those that suffer some kind of mental disorder, since they fear looking for a psychiatrist, being labeled and then for that label to never disappear.
And this causes them to not look for professional help, as they play mental gymnastics thinking that if no professional has diagnosed them with an addiction then they are not addicted, forgetting that what matters is not the label but the reality, and someone which spends most of their time and their money gambling is an addict, regardless of how they try to soften and alter the truth.
Maybe there is a fear of gambling addicts that if they reveal their gambling addiction to other people, they will be rejected by people, making them unable to accept it. And that's what makes gambling addicts not want to admit that they have a gambling addiction so they don't dare to be honest with other people. But if they don't care about what other people will say, they will still say or be honest with people that they need help and want to cure their gambling addiction. That will allow them to get the right treatment to cure their gambling addiction.