While true the problem is going from not controlling yourself when you gamble to actually do so can be extremely hard, after all those unbridled emotions they may feel when they gamble with money they cannot afford to lose are something they are not going to feel at all once they control their gambling behavior, and in that case they will always be tempted to go back to their old habits, and for someone like that it may be a better idea to give up gambling completely before they do so.
If they lose self-control while gambling, they can forget to take care of themselves and will instead be tempted to continue gambling which can cause them to lose all the money. Even though you have allocated the money for gambling today, but because you lost self-control, you forgot and used all the money instead. That is a mistake that we must correct immediately so that it doesn't happen again in the future or when we gamble again. We must be able to resist the temptation that comes in the form of attractive promotions provided by casinos, especially if we really want to limit our gambling time.
I think any gambler who actually claim to have set aside a certain amount of money for gambling, and then later on go ahead to gamble past the money he or she has set aside, i personally assume that such gambler never did set any money aside for gambling in the first place, yes i do agree that losing self control can cause a gambler to gamble above limit, but to the extend that such gambler will not know what he or she is doing, A gambler who loses money to gambling and come back to start regretting is not but a kid, and kids aren't supposed to be gambling, they are supposed to be in school studying.
Don't miss understand the point or where I am coming from, there is a difference between staking much more than one can afford to lose in gambling, and regretting after loosing the money, from playing normal gambling and losing, then regretting, for the former, the regret is understandable, but for the latter, the gambler before engaging in gambling should have known that its either a win or a loss, and which ever comes, the gamblers should take it wholeheartedly.
I'd bet you've never been on the front lines of a casino floor, feeling the tension, the adrenaline. Its not as black and white as you paint it. Yes, there are gamblers who act immaturely, but your harsh judgment of their decisions is entirely baseless. Economically, the value derived from a gamble isn't just monetary; it's experiential. And to just throw around terms like "kids" to belittle them? That's low. You ought to walk a mile in their shoes before throwing stones.