"No individual religion can or should dictate whether a space mission should be approved ... we do not and never have let religious beliefs dictate humanity's space efforts," Chafer said.
We're not telling them what to believe but they don't get to restrict us on the basis of their religion, especially when it comes to doing things outside their property rights.
If the company was burying people on Navajo land, then the Navajo would have some basis for complaint, but nobody owns the moon and some human ashes on it will change nothing.