Why, because they are too idealistic, they are too young to make logical judgements, relying on emotional beliefs. Fairies at the bottom of the garden make more sense to them than the realities of life.
If indoctrinated at an early enough age and for long enough then you too would more than likely succumb! This may last a life time for some but others who have more insight and maturity change completely, do an about face. This you often see in voting habits as you get older and hopefully wiser.
