I mean, I can understand the Flight Attendant needing to have the dog (and the carrier) in a place that was safe for the other occupants of the airplane.
But putting all the blame on the Flight Attendant is, in my opinion, just plain wrong.
The dog was with the owner, and the owner had a responsibility for the dogs safety.
If the Flight Attendant insisted, she (the owner) should have gotten off the flight. Simply refuse to put the dog there. Get off the plane and find other transportation.
What if the Attendant had insisted that her infant be placed in the overhead bin? Same-Same, as far as I am concerned.
Simply refuse to do so. Yes, it is inconvenient to take that path, but, at the end of it all, it is the pet owner who made the choice to continue the flight with the dog in the overhead. It was her responsibility to ensure the safety of the dog, and her responsibility for what happened. She failed in that responsibility. Yes, the airline shares some of that responsibility, but the owner allowed it to happen.
At some point, one has to simply say “NO”.