Because she used to have a lover.

His name was Kuekuatsheu, and they lived in the spirit world together.
And every night they would wander the skies together.

But one of the other spirits was jealous.

Trickster, wanted the moon for himself,
so he told Kuekuatsheu that the moon had asked for flowers.
He told him to come to our world and pick some wild roses, but Kuekuatsheu didn’t know that once you leave the spirit world,
you can never go back.

And every night, he looks up in the sky
and sees the moon and howls her name.

But he can never touch her again.