These observatories aren't causing environmental problems (AFAIK); they're great tools for humanity to understand our universe. There aren't many locations on Earth that have the advantages this location has, yet these people want to stop this for what? Irrational superstitions? If this were some corporation trying to do mountaintop removal mining (like they do in West Virginia), it would be perfectly rational to oppose that: that's an environmental catastrophe. But this is not, this is one of the most benign things humans can do.