It's called "foreseeability"
"So the state recognizes that leaving a car running in a public place in and of itself, is not a danger."
Nonsense. First, the mere fact that an insurance company paid for a car stolen, in part, because the irresponsible driver left it running while unattended is NOT "state recognition," whatever your fantasies are.
Second, "leaving a car running in a public place" facilitates the very likely and foreseeable consequence of someone stealing that vehicle, whether a kid who sees an opportunity for a simple joyride or something much worse. If YOU created that likelihood, you could be held liable for it.
"I only leave my car running if it is hot out, or cold."
Well, glad you narrowed it down to those emergency situations.....
"Because once the state says I can't leave my car running on my property, then the state forfeits its right to govern in my book."
Your "book" is irrelevant. Try a REAL book - a law book. Here's a start:
"G.L.c. 90, § 13. Safety precautions for proper operation and parking of vehicles:
No person having control or charge of a motor vehicle, ....., shall allow such vehicle to stand in any way and remain unattended without stopping the engine of said vehicle, effectively setting the brakes thereof or making it fast, and locking and removing the key from the locking device and from the vehicle."
Got that? LOCKING AND REMOVING THE KEY.
And for those cretins who leave kids in cars:
"102 CMR 8.10: Supervision
Children in Vehicles. A caregiver must never leave a child unattended in a vehicle."
Concise, precise, direct. Don't leave kids alone in cars.
In short, don't facilitate crime and the consequences thereof by virtually GIVING a running motor vehicle to anyone and everyone who strolls by. Would you leave your gun on the counter of the coffee shop while you dashed back to your (running) car for your wallet? Both are lethal instrumentalities.
"If you can not understand that, than the liberal school system has done well."