The article is correct, but you have to go slowly at first, and learn to listen to your body and learn your limitations.

They pushed you too hard too fast when you had outside PT. It was f***ing ridiculous. When you are thinking about the validity of that article, I wouldn't factor in those experiences at all. Think about your in home PT sessions, which were much more appropriate given your physical limitations and level of activity... you seemed to do well with those exercises