Excellent points, Alicia.
There are folks who have been dismissed and invalidated for a long time, by friends, family and doctors. They need validation, first and foremost. Often they have found that validation in an online support group of others who are also suffering. Those groups can be very helpful, but they also can act to imprint the ideas that their suffering will never end, that they have a disease that is completely incurable, and that they can only cope with it as best as they can and wait for a miracle medical treatment to emerge.
Rocking that boat can be met with a lot of anger, understandably. We need to tread softly with these folks and recognize that they may never see things from our point of view.