I think it unfortunately boils down to externalized shame from MDs who can't admit they don't know something, mixed with old biases about neurotic women who make up ailments. Nearly all medical knowledge is based on rote memorization in med school and received tribal wisdom during residency. MDs aren't given the time and mental space to really sort out which things are true and which are superstition while they are in training.

Ideally the check from a knowledge perspective is CMEs and a separate group of medical researchers that inform med school curriculum, but there is no real check on the eye-rolling and "oh, you have to deal with one of THOSE" that they are exposed to during residency.