I'd assume some connection to the
Lesser Keys of Solomon and the works of Aleister Crowley?
Occultism isn't Satanism: the Lesser Key of Solomon is about commanding and binding demons through magic, generally invoking angels and God's holy name, or telephoning angels for secret knowledge. Certainly heretical bodgery, but not Satan-worship: demons are meant to be commanded and abjured and there's warnings layed out like mile markers in the book about how demons are wicked and will try to trick you into damnation (along with how to avoid it) and God is at the top of the totem pole, deserving of worship.
Crowley, meanwhile, mucks about a whole lot with Egyptian mythology, and while he does talk about Baphomet, he insists that it has nothing to do with Christianity (indeed, Thelema views the entirety of the Christian metaphysics as nonsense meant to prevent people from attaining enlightenment). Furthermore, while Thelema is certainly Dionysian, it isn't the carnal and exogenic practice that is associated with the Satanic conspiracy theories or cursory examinations of the sect's attitude: Crowley cites Muhammad, Lao Zi, and Buddha as men of high spiritual attainment, and his command "do as thou will shall be the whole of the law" explicitly does
not mean a hedonistic lifestyle: Crowley talks a lot about the "true will", which could be better understood as something like a calling or personal mission, and states that
this is the will that should be done, not the carnal desires of the ego. Fairly typical of the Spiritualist movements that arose during this time, and quite similar to hippy "New Age" beliefs, as well. Hell, look back before Crowley and you'll see half of his ideological blood flows down from the line of Millennial Christian cults that arose in the mid-19th century.
The sexual practices discussed by Crowley are far closer to the Hindu
Kama Sutra (complex, ecstatic sexual practice as a form of ascetic activity, with animal gratification being the furthest thing from your mind when engaging in it) than a Caligulan orgy.
This, along with the fact that most Satanic conspiracy theories allege that these Satanists have held high station and power in society since, at least, the early Middle Ages (predating both by nigh on a millennium) means my question is still unanswered.
