Well, for one thing that wasn't a full grown grizzly...it was maybe a year old at best. Get a couple more fights under it's belt and the fight might have come out differently.
As for the cougar, ever had a regular housecat scratch you? Now imaging those claws 10 times bigger and 10 times sharper....
In addition, that bear was probably more curious than anything. It didn't really make a concentrated effort to get to the kitten....As for the staged look. I bet they were getting shots of the mother and the kitten with multiple cameras and cameramen. I'm amazed at some of the shots the nature photographers get without staging. Just remember they probably shot 100 days of footage to get that one 10 second clip......