I’m an old guy. I think there are a few things that influenced this. For one, there’s a basic kernel of truth in that we tend to be more naive when we’re younger because we lack experience. We’re unrealistic about what’s feasible. Lots of folks also get a bit more jaded as they get older because it’s hard to see the same bad shit over and over and react to it the same way the 100th time as you did the first time. Throw in that folks were generally less politically polarized for the older generations. Conservative vs liberal, for average people, tended to be more about how much money we spend on defense and how much on social programs.
So a lot of people moving through that landscape did feel that some of their liberalism came from unrealistic idealism. But things are different now. We’re so polarized, and the wedge issues are so fundamental to peoples’ lives. I know, I was personally raised in a relatively conservative household, and I’ve grown more and more into a flaming liberal because I see conservatism as an assault on personal freedoms and on science.