One reason you don't see that is that that's not the AMA's function. The AMA is a lobbying group.
> the redefinition of a disorder because of a change in societal norms seems different
Different how?
Early accepted medical practices were often barbaric, and not effective.
When we learned more about the human body, we stopped doing those things.
Much can also be said about the many fields of science, and the giant shifts that were necessary as the fields matured.
I don’t see the AMA voting to declare something that is a disease is no longer a disease. (Although maybe I’m wrong — alcoholism and addiction are now a disease.)