It is definitely a problem when a teenager is gambling with money that is not even theirs, however most of the time this is just part of what being a teenager is about, as when we were that age we did all kind of crazy things that when we think about it the first thing that comes to our minds is what were we thinking? However an adult that is also in that situation is a completely different thing, as they are immersed in a very unhealthy dynamic with their family by not earning their own money at that age.
That's exactly the point, so IMO, no blame to cast here. As a teenager, you can get some pocket money from your parents, or you could even have some rich uncles and aunts that can give you anything you want as long as you just ask them for money, they can give you. Yeah, it is quite understood that teens do some sort of crazy stuff and cannot really take the blame for all. As a teen, you can decide to do anything with the pocket money you receive, whether you use it to buy some snacks, play video games, or gamble. The reason is that you are not yet old enough to be dependent on yourself or start making your own money. But for an adult, it does not make any sense to still be fully dependent while the person is not disabled. Perhaps the person is physically and mentally fit but just too lazy to work, make money, and use their money to do whatever they please.
Basically, the word "dependent" makes it sound like you are incapable of making money, but there are other ways too. Like for example your father may have 100 houses that he rents out, or he owns a huge factor that makes millions of dollars, that makes you not needing to work, if you have millions of dollars worth of income, and your father gives you 100-200k a month, why would you work? If you do not want to, then you do not have to and that is totally understandable without a doubt.
However, at the very same time, we are talking about a situation that would be different if parents are forcing themselves if they are trying to look after you, that's not what I mean. In the end, I agree that teenagers makes mistakes, that's understandable.