Ok, I watched it. And yea, she's a worry wart who overstates the risks of a lot of things but at the same time I think some of the criticisms here of the video are a little overstated, too. She's not saying NO dogs should ever back up or crawl or do stairs or do agility, she's saying what the PT told her HER dogs shouldn't do (which seems kind of weird to me, but whatever she wants to do, I guess). She's not saying dogs shouldn't do ever do position changes, she's saying she felt like asking for the super fast flashy down from a stand was hard on her dog physically. She's not even really saying agility is bad, she's just being super, super risk averse.
I think it's a bit silly to suggest people need to take their dogs to a PT before starting any sport, and I think she worries way too much about things that might possibly maybe theoretically happen, but her overall message isn't a bad one, I think. It's not a bad idea to step back and think about why you're doing something with your dog... although I also think "are you doing this for your dog or for yourself" is a false dichotomy and it annoys me - there's no reason it can't be both.