Winning is not the problem rather greediness is the main culprit that makes you pursue more to bet when you are already in profit.
I personally don’t view winning with negativity despite the example involved since I knew that it’s not the winning but greed. Losing or winning greed is the common factor why people lose in gambling.
Not being contented with your win can be one of the reasons why you might end up losing more, you have a point on that. The main reason why a lot of people lose after winning is because they chase after more wins and as a result of this they end up throwing their stake and profits away. Gambling is a game of luck and whenever you get lucky it's important that you take advantage of it and stop chasing