Op you are right. It is because they want to get rich overnight and they believe gambling will make that happen.
Gambling is not a short cut to get rich, the probability is very slim. Normally, whenever you feel like gambling, make sure you set a gambling limit. When you exceed that limit, stop immediately.
I will advice everyone to set limits in their gambling. It could be daily, weekly or monthly and make sure you adhere to it.
Those who expect to get rich overnight with gambling won't follow a limit they have set, and those who understand that getting rich through gambling is not possible won't need a limit because they would already know they don't need to spend more money than they can afford to lose since it's a senseless thing to do when you already know the money you are spending is getting wasted and all you should be doing is trying your luck with a specific amount and stop if it's lost.
We see so many people who lose control when they get into gambling. Those are the type of gamblers who think they can make a fortune from gambling without realizing that gambling is only profitable for the casino and not for gamblers since gamblers are customers and customers only give profit to the business owner and don't get profit from the business itself.