I find these quizzes interesting even though I am terrible at trivia and consider most of the information outside of my interests. There certainly isn't much about Satanism there, but the nature of things simply makes it impossible to keep up with it all. The more you read, the more you will need to read, but it's mostly irrelevant on a practical level. I feel Satanism (either way) is very simple and doesn't require historicity to demonstrate its value to the practitioner.
And while I think Kenneth Grant and Crowley are important figures, I feel neither of them would consider themselves LHP - they are relevant only in the way that a pair of scissors is useful to most people to cut paper. Some people are interested in the "scholarly pursuit of the LHP" in contrast to the "experience of the LHP", and that's where I am l stuck - I am too busy doing to read all that crap.