Young people change frequently; it is a common life stage.
It is a time where most changes occur, and it is when the most important changes and opinions are shaped, but recently young people have evermore platforms to communicate their ideas and to form solid ideologies. These ideologies, although somewhat rooted still have not stayed nor have they been applied to their lives *most of the time, therefore it is subject to change in the upper stages of life or simply the next day when the young adult sees that their ideology is not practical.
The point being that young adults form ideologies from the first source of information that they get, and it is pretty rare to double-check their information, or check it at all. Perhaps they are reading on a subject, but the essay is extremely biased therefore passing on the bias and so on. And when they find a new source of plausible, valid information they quickly switch their views.
Life experience and the vicarious view, not of the world, but of those around you mold your identity and ideas, but with the vacuous experience that the young mostly has, filled with laughter and idealism, every opinion is moldable and eventually changed whenever experience tells them otherwise, or not thereof.
Young people, relative to their older counterparts, the one who writes the books, lack the inherent experience that comes with age. Therefore, they are capable of forming coherent arguments for their views, but when someone with a better rhetoric, for good or bad, challenges them to question their beliefs and to accept theirs, the young man is quick to answer to the impulse that it begets this rhetoric into their ill-formed brain. The young man is moldable up to a point where their life experience is enough to sustain their beliefs, and subsequently this beliefs root in the man and make it harder for anyone to change the subscribed to agenda of a person.
This is why a young man is stubborn, but their questions and rebuttals are vacuous (most of the time), but if the rhetoric is good enough their beliefs get changed, and an old man is stubborn and no matter what you will not change his ways, because the illusion that their life experience supports their beliefs is rooted deeply in their minds.
This is why there are so many ideologies and branches of thought, literally because of stubbornness, but also because of the illusion that somehow their life experiences sustain their beliefs, and they do this by warping to the image of their beliefs whichever stimulus they seem to receive. A poor man is seen as a man in despair and in need of help by the socialist, but is seen as a poor loser and drug addict by the greedy capitalist. Our minds are molded by what our minds want to see.