Declaring something sacred is either irrelevant, or it is an attempt at theft.
If you own something, then you get to say how it is used whether or not it is 'sacred'.
If you don't own something, then declaring it sacred is an attempt to deprive the owner of the freedom to use it as he chooses, and is morally wrong.
Surprise, surprise - religion once again reverses the arrow of morality, and declares their wrongdoing to be a moral imperative
If these Hawaiians want to claim that the telescope(s) should not be on the mountain because it's their fucking mountain and they didn't give permission for telescopes to be built there, I would be happy to see a court, or even a legislature, consider that claim, and make an appropriate ruling or law to protect the rights of those with a reasonable claim to ownership. There are good reasons to re-visit ownership claims in many places around the world, where indigenous people have had their reasonable ownership claims ignored or unreasonably overruled.
I don't know the details of how this particular area came to be owned by whatever entity is the current legal owner; if some unlawful or immoral act was involved, then it might be reasonable for a court to consider changing the current ownership of the land. But that has fuck all to do with sacredness, and everything to do with establishing lawful possession. "It is sacred to me" is not a reasonable basis for a claim of ownership.