Zephyros
How does that single quote say anything about either Aleister Crowley or the Thoth Tarot?
Haven't read the book, but I have read of others who misconstrued "Do What Thou Wilt," understanding it as "do what you want," and used a shallow understanding of the maxim to justify terrible deeds. This isn't different from people saying "the Devil made me do it" or a thousand other ways people shirk responsibility for their actions. But, as you say, it has little to do with the source.