Ugh, I'm sorry these comments were made, Jenni. They sound triggering, especially with your experiences of your mother's constant criticisms. I do think, like others, that this is mainly related to your grey hair and based very much on what the individuals have been exposed to regularly in their own life.
I also appreciated skimming the other stories. My experience: I made a dramatic decision to go very short in 2017 and kept it that way until 2020. When I decided to grow it out I took the opportunity to stop coloring it. I had also just started in a male-dominated and very technical job (I've always been amongst mostly men at work but this was the most extreme), and most women I was around at work were years younger and very simple, casual dressers. So I suppose my decision to grow out the color was an attempt to fit in by being more low maintenance but also to assert my experience. It was fine during lockdown, but as soon as I started interacting with the world again I HATED the way it made me feel, and I felt like I couldn't really look in a way that expressed who I felt like I was. I certainly wish for feminism's sake I could get over feeling this way about aging, but I've greyed a lot at a young age and perhaps going from brown to salt and pepper with white streaks was too much at once.
Anyway, now I've got a lot more comfort and confidence at work and have started settling in to my style after a pretty big upheaval (2014 with my first child, 2017 with a major job change). So I'm CONSIDERING growing out my natural color again. Unfortunately I have a non-pixie cut I quite like so it won't be quite as convenient this time around.
ETA, I also acknowledge that a large part of my dissatisfaction with seeing myself in grey hair was that the church I grew up in did not allow women to color or cut their hair, and most women pulled it back, either in elaborate updo's or scraped back into a bun. I associated that "look" with that kind of repression of personal style/frumpiness and I think it's taking me time to heal from those experiences and see my natural locks as something that CAN be beautiful and represent how I am as a person.