Then I must be a rare American. Problem is, humans can (and do!) lie. Dogs don't. At least, not that I've ever caught one in!
All life is sacred. But animals depend upon us to take proper care of them. That means that if it's hot outside, dogs, cats, gerbils, what-have-you, don't get locked in a vehicle with the windows rolled completely up, unless the car is running with A/C turned on. To be sure, some vehicles run very quietly, making it impossible to tell that they're running. So, I would say: check the exhaust. If you feel pressure from it, it's running.
Also, stop and realize that not everyone truly cares animals. You do, and take precautions to keep your buddy from being hurt or injured, or worse. Doesn't mean that everybody is like that. Why do you think laws regarding animals being in the vehicle during extreme weather were made?