I've always wondered about this. What exactly should you describe in an alt text? Are there established guidelines one could reference to determine what is appropriate?
Accessibility guidelines in the alt spec used to say "correctly describe the intended purpose of the image if the image was missing or unable to be loaded".
It would have probably been a bit more on the nose to be like "A woman of a non-white race showing our agency is capable of diversity"
[0] - https://research.fb.com/videos/automatic-alt-text-for-photos...
[1] - https://www.theverge.com/2019/7/3/20681231/facebook-outage-i...