I think personality disorders are a problem because they are more threatening to the caregiver/doctor. It's like the difference between a person who has a rash versus someone with leprosy. The former is treatable (with meds, maybe) while the latter feels both threatening and contagious (maybe this is a crap analogy through because if leprosy is treated early enough it clears up!). It takes a special person to show empathy for someone who has an illness that might be dangerous. And it's just a real shame because as Keith G. pointed out, below, PDs are mostly the result of horrific abuse.