Why is it that the people who most revere the past are so ignorant of it?

Longing for a past golden age that never actually existed is one of the hallmarks of fascism. I'm not saying everyone who is nostalgic for the era of their childhood is a fascist, but when it's combined with racist nationalism, a belief that the country was betrayed by a specific group, and that the golden age can be restored with violence, that is fascism.