“Most of the 70s survivalists were Mormons.”
I would like to see your evidence for that, I considered myself a part of the survivalist movement then and I never read or heard about it.
I first became acquainted with the survivalist movement in the late 60s, through my ex-wife’s family, all of which were Mormons. One cousin in Ogden seemed to be on first name basis with several of the camp founders.
The non-mormons came along later around 1974 or so, as the movement gained notariety through news accounts.