yeah, that article was a real laugher. The Rainbow Warrior myth exists in numerous nations' legends, the most recent being the prophesy of Crazy Horse. I know nothing of that book's relationship to the rainbow gatherings other than they somehow latched on to the quote falsely attributed to Hopi prophesy. The rainbow hippies were taught largely by Lakota and Hopi elders.
Swan made a complete fool of himself, the grandmothers and warriors from the rez choosing to join the gathering instead of his blockade and the intertribal council rebuked him for speaking for them without their consent.