But it also says that the Ten Sefirot are not considered to be separate deities (but rather, attributes of one).
I read some commentaries by rabbis after Madonna announced that she was delving into some Hollywood revision of Kabbalah study. The rabbis had written that Orthodox Jews are discouraged by some from reading the Kabbalah at all, and by others, from reading it until they have read/written the Torah (long term undertaking) and been Orthodox Jews for a very long time.
Personally, I carefully avoid any and all polytheism by avoiding all mysticism (including increasingly popular "inner light" doctrines) and spiritualism (talking to the dead, dead being omnipresent, etc.). I study, having started with "In the Beginning."