It's a really weird argument, you're basically saying that people shouldn't be allowed to upgrade their infrastructure ever? Imagine saying that for some poor country: "Oh, well, they either had no running water before, or they knew the situation before moving there, so screw them, they can just continue walking 5 miles every day to bring water from the spring".
Also they've been without that road a lot longer than 40 years, King Cove exists since at least 1930s. Population is dropping so I doubt many people have been moving there, most of people live there their whole life....and if they get sick or injured and planes can't land, they're screwed without that road.