we just get more averse to bad ideas, or have heard it all before.
When I think back to when I was younger (I'm 47) I realize how simplistic a lot of my beliefs were. These days I'm far more willing to listen to others and I make a lot fewer assumptions about why people do the things they do. I hope the trend continues.
I think that's why I was a little sympathetic to that Google engineer that was recently fired for his memo arguing against Google policies on diversity. After I read about what he argued, I actually said to people that he sounds very young. His recent statements about the positive aspects of the KKK reinforce that.