> "The planned construction site is on land considered sacred by some Native Hawaiians."
What the *modern* natives fail to mention is that the *pre-western* natives used the top of the mountain as a rock quarry. It wasn't sacred at all. Turns out that lava erupted during an ice age, when there were glaciers on top, hardened rapidly, preventing crystal growth. Crystals fracture more easily, so the lack made for excellent stone tools, which the natives used before westerners brought metal tools.
The top of the mountain wasn't habitable for the same reason it makes an excellent telescope site - very little rain. The altitude also means it's cold, and it is high enough to induce altitude sickness if you are acclimated to sea level. So the natives didn't live up there, but rather set up mining camps to extract the rock, then took them back down. There is literally tons of archaeological evidence all over the Mauna Kea Science Reserve, the area on top of the mountain that the University of Hawaii controls. The astronomers are careful about not putting a telescope in archeology areas. There's rock debris, partial tools, shelters, etc. up there.
If it was originally an industrial site, I see no reason not to use it now for a scientific site. It's not like they are knocking down the Parthenon to build a telescope.