Exactly the point, casinos shouldn't ban gamblers for winning too much but unfortunately they do even without remorse, and most times, it leaves me wondering like, were the owners of this casinos expecting all of their customers to simply keep losing heavily so that they alone keep making money? If they ban gamblers for winning too much, they should also be banning gamblers for losing too much as well but this they don't know because they enjoy it when gamblers lose.
Reputable casinos don't actually ban though, they limit.
They either limit the amount of money you can bet on a game anytime you are betting in a league where you constantly win, or they limit you from betting on that league completely or to a number of games you can bet on per day or week, this is better than getting banned completely from accessing the casino simply because of too much winning, looks very unprofessional on the casino's side.
You have valid point banning after huge win going to hurt their business because now in this social media era its never been easy to have things like these, but surely they can limit this or many already have limited about their games because they understand consequences just because of this fixed amount how much and winner can take from them.
Sometime back I was on a casino they have good system and when I start a game there was a message about maximum and minimum wins because they are still in business, and they are doing good job without having any issue always having things on level works for all stakeholders.
Currently, few crypto casinos are doing unlimited gambling because they can afford this with their games providers are also solid this is doing good for all.