The point of the show, for me anyway, is seeing people challenge themselves as they compete against one another. If they have prior dancing experience, then they challenge themselves to do dances they've never learned. If they have stage fright, they take a deep breath and get out there and perform in front of a live audience and millions of TV viewers. If they have MS, they make the most out of their body's limitations, and try their utmost best.
To say that it was painful to watch Valerie, and that it spoiled your entertainment, offends my sensibilities. She had as much right to be there as Cloris Leachman or any of the other older woman who have done this show! What was so painful to see? They weren't showing clips of her getting her medication. They weren't showing her brushing her hair with tears in her eyes as clumps came out. She never asked for anyone's sympathy - she shied away from that! And she never asked to be the face of this awful disease. Her reason for being there was so she could "Carry on!" And kudos to her for that!
Fanny, I see you were posting while I was posting. I totally agree with everything you said.