So the gambler has to keep in mind one thing while gambling that he should gamble through his self control i.e. not to get over addicted. I don't consider gambling as a crime but over addiction to gambling is a crime because there is a high chance of losing. If a person gambles according to the plan, he will take a break even if he loses the gamble or wins. We see this trend among professional gamblers. They set a certain amount of money every day and then gamble with that money. On the other hand, those who are over-addicted never want to give up their gambling. Every person who gambles should gamble according to a proper plan.
Gambling should be a hobby of sorts and be experienced in such a way. It's not going to be a main source of income for anybody, but it should rather be a way of getting entertainment and thrill once in a while. That is how, in my opinion, there wouldn't be problems that you described, with sums that you are okay to spend in mind.