For old people they believe that its a dirty money so every one will stay out of gambling, but for modern people they don't think it as dirty money,some people play using calculations and strategy, so they do hard work of research to make profit
Why do you think that old people believe that gambling is dirty money, gambling is not a new phenomena and it has roots for centuries and you think that old people think that it is dirty is not the correct way to think, yes gambling has destroyed many lives in the past and may be that has created a misconception for some people but one fact is that what ever calculation you make there will be no certainty when it comes to gambling, the probability factor always shows that you loose and luck is a major factor.
Well, we can't argue this since that is their belief. Besides we respect them and their beliefs as well. Probably that was a religious belief that gambling is bad to people and if you have a profit on this it is dirty money. Each of us has a different understanding of gambling and also the generated profit. Indeed, all I can say is do what you have believed if you want to gamble but against your religion then, leave your religion and find those friendly in gambling.