'With these new opportunities and new ways of doing business, we recognize that some non-NASA commercial payloads can be a cause for concern to some communities.'
If I remember my Navajo mystery novels correctly, this is specifically because the Navajo/Dinee consider corpses to be ritually unclean. I guess the equivalent would be taking powdered human waste up to the moon and flinging it around just to say there's human DNA on the moon (I'm sure all the moon missions left their waste behind anyway, there's already human DNA up there).