The way I perceive it is that if a person who is not cheating or engaging in illegal gambling activities consistently wins, the casino is highly likely to ban that person, just as they did with Dana White.
This is actually a measure done by the casino to avoid their business from collapsing, as someone like Dana White can cause their business to end. Because not only gamblers can lose huge amount of money, but also the casino itself. But I don't think it's right to ban someone just because they were that "good" in gambling.
Unless if they had won dishonestly and that they committed any cheating activities or offensive considering the terms and conditions of the casino, I think it’s fair to ban them if they have done something like these. Maybe casinos can think of other ways to regulate this kind of matters, because I believe that banning someone is not an answer to this as it can deprive someone from engaging in such activities.
But again, it is the decision of the casino as they still have the power to ban and prohibit someone from engaging in gambling.