If you choose to call them dumb working animals, be my guest. I'll stick with the word I chose. If you can show me one dog that arrived on the scene by itself then you would have a point. Look, if we say a working cadaver dog is a "hero": then what do we call the firemen that ran into the building as others were running out? I will leave it at that.
I think we all agree that the firemen and police and EMS that were going into the building were far beyond heroic. I don't think we have a word to describe their actions, to be honest.
You'd have to know these animals and their trainers to understand that yes, they ARE heroes. These dogs do it for the love of the humans they work with, and many have been injured. Paws slashed by iron, dust choked; one was even buried in rubble. All (as far as I know) returned to work again.
If you'd ever watched them as they worked, or if you ever saw how these dogs are the last hope in finding the lost or endangered, then you'd understand. If you are ever lost, be looking for the dogs - chances are, they will be the ones looking for you...