It’s human nature, weak minded humans will always do things & continue to do things that are bad for them. Not all of us are strong minded unfortunately.
The weak will be weak.
I think they don't realized it is bad for them, they might be thinking that is it the best way for them to earn big money. And I disagree about the weak will be weak because not all weak remains weak, most of them get stronger and stronger overtime when faced with difficult situations, I guess they just have to experience the worst scenario for them to realize their weakness.
Yes, they don't realize the bad things, but I am sure that some of them will have a strong will to change their lives and they will try not to be weak anymore. They will have the awareness to know the reason for gambling, and they will not repeat to continue gambling because they don't think that gambling will be a way to make money.
Once we face difficult situations, our awareness will come and wake up us so we can know and think about what the mistake we have so we don't have to do the same things again. So, in this situation, there is no valid reason to continue gambling.