It turns out that actually standing by "men and women are not inherently very different" is a reliable way to bother absolutely everyone. Left or right, cis or trans, feminist or misogynist, all cling to the binary for dear life.
My mom, who is a left-leaning, generally feminist woman has many times expressed opinions that she thinks men and boys are more likely, based on biological traits, to be more violent and rude. It bothered the shit out of me because my sister and I are both assigned male. And when I'd express that to her she'd say she's not counting us, or something to that effect, but that always felt like a copout. She couldn't except that it was a learned, cultural thing, she just thought my sister and I were exceptions. If anything, it was a little othering. It was especially bad when she applied this to children, which she did because she worked in childcare. And I can kind of understand her viewpoint, assuming she saw patterns in the ways boys behaved in her years working with them. But the thing about that is that biology is not an adequate explanation for that behavior, because, prior to puberty, there is very little difference in the levels of sex hormones of males and females. She would use the word "testosterone" a lot, as if young boys had significant testosterone in their blood. They don't. Hearing her bullshit time after time has only radicalized me. If you want to make social progress for women, for trans people, for people as a whole... You need to accept that male and female humans really aren't all that different from each other.
People are also really prone to confirmation bias when thinking about groups they see as distinctly separate.
One example I have mentioned before is that my father used to believe women are worse at driving than men. Whenever he saw someone driving badly he'd try to look at who was behind the wheel. If it was a woman, he'd make some misogynistic comment that reinforces his worldview, but if he was a man he often just didn't say anything (even if he was like "I bet that's a woman" before) and just didn't think about it further.
People are also very prone to making generalizations about groups while ignoring differences within groups.
They feel comfortable saying stuff like "Boy children are very different from girl children" but have they noticed that the boy children are also very different from each other, for example? It ends up sounding really sketchy to lump huge and diverse groups of people based on something like gender and treat them as if they share one personality regardless of their individual circumstances.
