After watching MSNBC's recent special on the Manson Family entitled Will You Kill For Me?, I'm convinced that the group was a Satanic cult, although the members did not necessarily realize it. Even Manson didn't necessarily know it. Satan doesn't care what we believe, as long as we do his will and become his puppets.
Promiscuity within the cult was a prominent aspect of the cult, and loveless abandonment to sexual impulses in a means of inducing an initial form of possession which facilitates SRA. The Tate-LaBianca murders strike me as an advanced form of SRA, meant to cultivate the will to kill, i.e. demonic possession. Everything else seemed to be intended to get them to kill, and to have a positive attitude about it. (I recall one saying that the more she killed, the more she liked it, or something like that.)
One possible motive for creating such cults might be to give the impression that Satanism is limited to unsavory characters such as Manson, when in fact it is fostered by those above suspicion in the highest levels of society. Manson was apparently a product of the Esalen Institute, a Tavistock spinoff, which traces back to the highest levels of the British oligarchy. This fits with my assertion that the Cult of Isis is the mother of all Satanic cults.