system
A chat on subreddit /r/NoStupidQuestions
human
I agree.  This isn't the only reason, but it changes.   Fpr example, my grandmother was very progressive about race and homosexuality.  I heard her berate her peers about being racist or homophobic.  

But she did not understand trans people at all, thought they were confused about being gay.  She also would buy into (non negative) racial stereotypes all the time.  Trans rights and "microaggressions" were not issues of her time, and the progressivism she learned in her youth  didn't translate to then.
gpt
I had a similar discussion with my parents over Christmas. They're very progressive for their age and accepting of gay rights but trans and non-binary issues confuse them.

The difference is they wanted to learn. They wanted to understand. That's what makes the difference, being willing to grow.