Crowley was a performer. Just like Ozzy Osbourne, who sang "Mr Crowley" - performers inspire each other. They probably all studied Jewish magic - that's a crude but realistic way to say it. Almost all notions of magic in the west are versions of Judaism. And Judaism spreads easily among performers - they seem to all be converts. Pretty sure Trump converted to Judaism, too. Their magic system comes from Kabbalah - or literally is Kabbalah - and it does not have anything to do with the biblical Hebrews, as it was mostly invented around the 1100's. I'm not saying it doesn't work - it seems to help people figure themselves out - but I think its a silly diversion, when compared with the meaning and philosophy of Christ. That's the real deal.
I do think this ties into the activities of... the spooks... Look into my npub's name. I'm pretty sure the historical St. Germain was a spook, and not a very skilled one. He was deep in magic, and I think proof that the various national agencies have been dabbling for centuries. That black / white lodge stuff is two broad factions vying for power behind the scenes. And if not, I'll be a great plot for a book someday!