I'd bet you've never been on the front lines of a casino floor, feeling the tension, the adrenaline. Its not as black and white as you paint it. Yes, there are gamblers who act immaturely, but your harsh judgment of their decisions is entirely baseless. Economically, the value derived from a gamble isn't just monetary; it's experiential. And to just throw around terms like "kids" to belittle them? That's low. You ought to walk a mile in their shoes before throwing stones.
The thing is that we are humans and not some sort of AI, and as such we do not operate logically and instead we use what we feel as a way to navigate the world, so a person could have the perfect plan when going to the casino about the amount of money they could expect to lose, but if something happens to disturb their plans then it is easy to just leave that plan behind and start doing what it feels right and then find themselves suffering a massive loss they never saw coming.