I'm not sure about this but from an observer's perspective, quite a few people are on a tight budget, their greed and bigotry towards finance and money is immense, that's the first thing I noticed from them. Plus, the second thing I realized, they are people who are extremely afraid of loss, for people with average and high finances, they have a lot of time and opportunity to start recovering from the loss. While people at a low financial level, their chances of making a comeback are extremely small in gambling, as soon as they lose at the first time, their psychology is broken.
Indeed, the number is smaller than those who have unlimited finances, but those who are poor also gamble a lot. One of the reasons, and I have also read this from studies, is that they try to get rich by gambling. So, this has become commonplace for someone when deciding to gamble. It doesn't matter whether he is rich or poor. Limited finances will certainly make it difficult for poor people to gamble again. But when they have a money, some of them will return to gambling. That's why I said, as long as he can still control it, it shouldn't be a problem. but the thought of getting rich instantly, greed as you mentioned, will be a trap for them.
The sad part about gambling is you can remain a poor person if you are only focusing on gambling, I know that lots of people want to become successful through gambling but it's almost impossible dream, those who don't have sufficient money always have a weird dream of hitting a jackpot, where as millions of people also have the same dream, and for a smart fellow this mean the chances of hitting a jackpot is very slim.
Rich people do gamble too but they have their strategies, and it's always better than those who have nothing and they keep throwing every penny at gambling with the hope of making big money.
It's for the greater good to gamble responsibly because no one knows what will happen tomorrow, while you are taking risks here and there always have something going on in your life, get a job, have some savings, start a business, and still be a gambler, just do it in such a way that won't hurt you and your future.