Although there are times you have to be greedy to get a mind-blowing win, so I don't really blame some of the gamblers that do express such greed which do later take all they have managed to win as well as their own pocket money they started with. Maybe if they can try to manage their level of greed and not go too extreme with it then they might have to know when it's the right time to leave with the little you have and try again the next day in within your affordable risk amount.
Your statement makes sense, as some gamblers lack the ability to control their emotions, leading to their inability to control their greed, which can lead to them losing their pocket money in the same day. Gambling doesn't have to be forced; it can be done at any time and at any time without having to spend it all in one place. Greed isn't a problem in any case, but if it's forced to the point of losing control, the resulting problems will be very complicated, as winning is an uncertain outcome.