I think the obsession with having been “born this way” largely stems from the idea that you need to be “innocent” to be guiltless.
If something is weird then you need to have no control over it, otherwise it would be mandatory to fix it. If I said that I had control over my stimming and could stop it at any time, people would request I do so. Not for my comfort but for theirs. If I said that I had control over my gender and could be something binary or maybe even cis, people would request I do so. If I said that I have control over my sexuality and could make myself heterosexual, people would request I do so. If I said I could control my attraction and could make myself monogamous, people would request I do so. If I said that I could control my disability and could choose to stop a flair up in its tracks, people would request I do so. They would never ask out of the goodness of their hearts, they would always be asking because I was annoying, concerning, distracting, or inconveniencing them.
Diversity is sometimes only tolerated if you have no control. If you have control, rules will be made to stop it. Hair will be straightened, clothes will be standardized, languages will be shushed, interests will be squashed, weight will be lost, and so on and so on and so on. Proving that we were born this way replaces the more obvious, that we’re okay this way. I don’t need to be a helpless victim of my differences to be forgiven for them. My differences aren’t crimes.