Today’s engines are no doubt better in this regard but used to be it took more gas to start the engine than it did to idle for a few minutes.
But to worry about those types of semantics misses a larger point. Its nobody's business if I idle my car. Its in the 90's with 95% humidity where I'm at right now - so of course I'm going to idle my car...for my personal comfort. Once that is deemed too frivolous in the fight to save Gaia, its not a big leap before the gubmint is controlling my house thermostat and limiting the number of showers I can take.