It is not that they were unexposed to world conditions during their teenage years. The difference is that their perception has changed. Unlike young adults, teenagers look at the surrounding world in terms of themselves and their impact on others. The technical term for that perspective is narcissism. Not to be confused with selfishness, it refers to the way in which youths see most everything in relation to the self.
Teens are in the process of forming a personal identity.
Therefore the world is a house of mirrors one walks through to find out what one looks like and who one really is. But young adults undergo a major change. Identity is pretty much intact. Less occupied with self, they turn their attention outward. The lens of their perception is decidedly wide angle in fact, it gains a sort of infrared capacity to see things in new ways.