When you've experienced something personally, like war for instance, you're going to know and remember personally how it felt to you, you will have strong opinions on it.
If it happened before your time, you will lack these feelings, and you will be basing your opinion on more abstract understanding that may or may not be accurate, since your understanding can only ever be as accurate as the historical material you were given.
Authoritarianism is a good example of this. It's seductively simple, and it sure would be nice if it "just worked" and we could live successfully that way. Sometimes a person needs personal experience of their own direct suffering before they can wake up from their fantasy, though, before they come to realize that we have the systems we do not because they're perfect or even great, but because they're demonstrably the least shitty of them all. Our way may be fairly bad, but other major ways are worse.
This is a very unpleasant conclusion to come to, and I understand why people may wish to hide from it inside their own fantasies of power and simplicity.
Authoritarian attitudes was the #1 predictor of Trump support if I recall.
I haven't lived through an authoritarian regime, but I lived through a terrible parent - so I've experienced the feeling of 'oh shit the structure that governs my life is fucked up and I must escape'. I think that's what made me anti-authoritarian.
I often wonder if there's a way to get people to shift away from authoritarianism. I think I get the appeal of 'simple, easy, you don't even have to think for yourself!' - but everyone needs to recognize those are trap cards.
I'm afraid I'm going to have to disagree with your thesis here. Many, many people who supported Hitler and Mussolini had been through WWI. Hitler himself was wounded in WWI.
It was certainly not intended to be a description of how things must or always be. Simply how they often work, it is one factor that goes into a very complex equation.
It is a large factor though. But not overriding or anything.
“Hard times create strong men, strong men create good times, good times create weak men, and weak men create hard times.” - G. Michael Hopf.
I was once talking about the Strauss-Howe generation theory with a conservative buddy of mine and the above quote is what he was familiar with and made sense to him.