Because younger people are much exposed to negative things now compared before. Our culture is also different and the source of information can be acquire anywhere using different types of technology. With this, younger people has more advantage and gambling is the one they have learn through this.
You are like saying that these young people are the only ones exposed to negative things but even in the past, even in my younger stage I am exposed to negative things too. Young peoplr are exposed to technology? Then they are exposed earlier on technologies, on games, on shows not on gambling.