Monica, I read the article. The physical therapist mentioned in the article was my physical therapist after I had rotator cuff surgery. He is very good.
However, on another note, I agree that any group fitness class taught by someone who has little knowledge about anatomy and physiology and has not had the proper training is inherently dangerous.
I always felt that there was much risk with yoga and at my studio I do not teach it or offer it. I have seen and trained with way too many clients who have sustained injuries as a consequence of yoga.
This is far from novel to me.
Thanks for the article though.