Nor does anybody! Again, most people realised this long ago. The scrutiny non-binary people are under is largely scrutiny they've aimed at themselves by claiming that doing what, as you yourself point out, people have been doing for centuries, is somehow new or revolutionary.

Gender non-conformity, long before it was called being "non-binary" was always met with resistance from society. We probably agree that this is a problem. One that has improved significantly in the past 50 years or so and I hope it continues to. But the "non-conformity" part of that is built on the fact that there is such a thing as a man and a woman and they’re expected to conform to the expectations society places on them. Pretending that if you don't meet the stereotypes you're something else, is actually the same restrictive BS, just in different words.

Changing pronouns (for a non-binary person, trans issues are different) is a meaningless linguistic affectation. It's like me choosing to be referred to as "raceless" instead of "black."

Okay, great. So what? Did I smash white supremacy? Did I end racism? Did I even remove it from my own life? Will racists now look at me and not see a black man? If I don’t like hip hop and fried chicken, do I need to move to a different point on the “race spectrum”? Or am I still exactly as black as I ever was and it’s the stereotypes that are the problem?