Calling a follower of Aleister "The Beast" Crowley not a Satanist is a distinction with little difference.
Satanist (or Black Magik practicioners) also take Christian constructs and pervert them, as you surely must know. Crowley took "The Beast" and Babalon from Christian references.
As to whether Crowley, Hubbard or Parsons were Satanists, I'm not sure it's a distinction worth arguing over, like debating whether Crowley was sick or just very twisted.
However, you are aware of Parson and The Church of Thelema, yes? And the moonchild? And Parson's "The Book of Babalon"?
From the RS article: "Parsons was also a follower of the English occultist Aleister Crowley. Parsons befriended Hubbard and invited him to move onto his estate. In one of the stranger chapters in Hubbard's life, recorded in detail by several biographers, the soon-to-be founder of Dianetics became Parsons' assistant -- helping him with a variety of black-magic and sex rituals, including one in which Parsons attempted to conjure a literal "whore of Babalon [sic]," with Hubbard serving as apprentice."
Doesn't matter what you call them ('Satanist' or 'Black majik')-- Parsons, Crowley and Hubbard were deeply disturbed men.