Correct, these are simply by-laws (aka Ordinances to our American friends). As such, they are only local. No "Canadian" law or overarching jurisdiction. These idling by-laws are more common in urban areas, presumably to help prevent pollution where there are massive numbers of cars in dense areas. Also secondarily to probably help prevent couriers from being arses, though that won't likely change. As it relates to potential ski areas, these by-laws are very rare in rural areas, if at all.
Enforcement (other than Toronto) is a whole other matter; there simply aren't enough enforcement officers to cover the larger areas. Idling more than 2 minutes? Prove it. Have them show you the evidence. Besides, you'll be long gone (or just shut off the vehicle quickly) if someone approaches with a big ticket dispenser in hand.
Perhaps well intentioned for certain urban areas, but really quite bogus and toothless in practice. One of those types of things. Nothing to worry about really.