Well, local people probably care about economic development and don’t give a rat’s ass about astronomy. So the question becomes, who’s going to compensate for the loss of economic development? (By local I don’t mean strictly local, in case of counter arguments along the line that there are no/very few local people to begin with.)
Disclosure: I’m a former physicist and I have personally operated an optical telescope with a 15’ dome, as well as a 60’ radio telescope, which probably puts me among 0.01% of world’s population. So I do know a thing or two and care about astronomy.
At Las Campanas, most of the staff from the cooks to the techs and a number of the researchers were all local. I found quite a bit of interest in the country as a whole as it's a source of national pride being the best location for astronomy.
Allowing this to proceed will affect _all_ future astronomy projects in Chile. No one is going to splash out on a shiny, new 100m optical telescope (OWL) if anyone can come along and park a city's worth of light just down the road.
What I want is TITBWTDI (this is the best way to do it).
It's dear to me because it came along at a time when I needed short breaks from thesis writing.