"How they handled it was not good, and too bad a manger didn't get involved."
Yes. That waitress showed poor judgement if that is the way it was dealt with. Volunteering to bring out another steak or entree is the way to handle something like this but OP said he didn't want to have it replaced. I wasn't there but from the tone of his post I can imagine it was a heated discussion resulting in the dog being fed the steak.