levite

I'm glad you asked this question (and I hope you won't be shy about any of the others that occurred to you)! Magic and mysticism is actually one of my professional areas of interest, so I am pleased to get the chance to say something about it. I hope you'll bear with me if I separate your question into three subquestions, and first one subquestion that was unasked, but lies in the background nonetheless.

1. Jewish feelings about Kabbalah. Not all Jews approve of Kabbalah, and historically, there have been considerable differences of opinion over the propriety of certain kinds of Kabbalah and certain aspects of Kabbalistic practices. First of all, there is a difference between what we might refer to as "High Kabbalah," which is a mysticism more oriented toward theology, philosophy, metaphysics, with elements of practice more or less limited to meditation, arcane readings of scripture, and certain esoteric contemplation techniques; versus what we might call "Low Kabbalah," which is much less interested in abstract philosophy and metaphysics, and much more interested in practical magic. There has, perhaps unsurprisingly, always been more tolerance amongst the scholars and rabbis for "High Kabbalah," and more tolerance amongst the average country folk for "Low Kabbalah." Sometimes the lines between the two have blurred, and it has proven disastrous, as in the case of the False Messiah Shabtai Tzvi (if you're interested, wikipedia him) who achieved fame as a wonder-worker and maker of amulets; and sometimes the lines between the two have blurred and it has proven beneficial, as in the case of the Baal Shem Tov, the founder of Hasidism (again, if you want to know more, wikipedia him), who was not only a charismatic and learned scholar, but also a famous magical healer and exorcist. But even in the case of "High Kabbalah," there has been a strong tradition of neo-Aristotelian rationalism in traditional Judaism, brought about chiefly under the auspices of the great philosopher and halakhist Moses Maimonides (if you don't know who he is, check out his wikipage), and that school of thought have consistently rejected mysticism of every kind-- although to me it seems to me that they just replace it with their own brand of mysticism. Today, many if not most Liberal Jews have a very post-Enlightenment skepticism regarding magic and mysticism, both in the "existence" thereof but also in the value thereof, regardless of "Low" or "High." The Orthodox world also has a chunk of people who don't hold with magic and mysticism, but more who do. That latter group is divided into those who believe in it, but think it is too dangerous and radical for anyone save the most learned, holy scholars; and those who not only believe in it, but believe in learning and teaching it.

2. Jews and non-Jews adopting Jewish language, text, and scholia for use in non-Jewish practice. Obviously, there is a line: after all, Christianity and Islam, as well as many minor religions, use Jewish texts or the reinterpretation thereof and Jewish language and practices for their own purposes, and we don't object. In my scholarly experience, most Orthodox Jews who are made aware of the existence of Hermetic or Western Qabalah (since there are many transliterations of the word, my usual practice is to spell the Jewish mysticism as Kabbalah, the Western/Hermetic systems as Qabalah, and the Christian mystical system as Cabala) are not comfortable with the usage, since much of the Western magical tradition embraces what we refer to as avodah zarah, which is sometimes translated as "idolatry," but is more accurately termed "foreign worship," meaning worship or spiritual practice forbidden to Jews or unintended for them. Such people view the adoption of Kabbalistic models and language by the Western magical traditions as an improper use by non-Jews of what is deeply esoteric and sacred to Jews. Personally, I believe that as long as practitioners of Qabalah do not claim that what they do is Jewish mysticism, or that Qabalah and Kabbalah are the same thing, there is little reason to protest. People borrow and swap cultural material: it happens. It's only when they imply continuity where none exists, or claim the mantle of Judaism without actually being Jewish, that I then have an issue. I would venture to guess that I am probably in the minority among Liberal Jews in even having an opinion about this subject. Many if not most are likely to be ignorant concerning either or both Kabbalah and Qabalah, and fewer still are likely to care.

3. Non-Jews (or, I suppose, in theory, uneducated or misguided Jews) practicing "Kabbalah" as a stand-alone system, or using elements thereof to assemble a makeshift system. This is more problematic. In part it has to do with what I mentioned above, with it being problematic when non-Jews attempt to claim some form of Jewish identity without actually converting to Judaism and practicing it in some recognized form. And in part it has to do with the fact that Kabbalah simply is not intended to be a stand-alone system. It is Jewish mysticism, and it is designed for use in living a Jewish life. Furthermore, Kabbalah is extremely, egregiously, unbelievably complex. To properly understand even the simplest level of meaning in the text, one must be fluent in Hebrew, relatively fluent in the Aramaic of the Talmud and other Rabbinic writings, and one must be deeply, deeply steeped in the scholarship of Tanakh (The Hebrew Bible), Talmud, Midrash (the body of literature comprising exegetical parables written by the Rabbis of the Talmud), the Apocrypha, and numerous works of commentators, halakhists, storytellers over the course of centuries, if not millennia. I have been studying Jewish text my entire life-- my father is an Orthodox rabbi, and my mother is a professor of Jewish Thought, and I was inculcated with Jewish scholarship from Day One-- and only within the last few years (I am thirty-six) am I beginning to be able to perceive the simpler meanings of the great Kabbalistic texts. Chances are, the random non-Jew who professes to follow "Kabbalah" as his system of belief in actuality has no idea what he is talking about. The bulk of the Kabbalistic literature has never been translated-- to the degree that it even is translatable. There are no shortcuts. I have met a couple of non-Jews who label themselves "students of Kabbalah," who are studying all these things, and admit that they may never acquire the requisite knowledge to properly comprehend what they study. So much I might accept. But I have never yet met a non-Jew who says he "does" Kabbalah who actually has taken the time to master the vast range of knowledge necessary to even start making sense of what is there. I doubt there are many, if any.

4. The Kabbalah Centre. If you read my posts, you'll know that in general, I try hard to respect the opinions of others, and to be polite even in disagreement. If you knew me, you'd know I nearly never judge the practices of others in religion in public without at least leavening such judgment with an admission that I could be wrong, or be misunderstanding. Therefore, it should be taken with some seriousness when I say that the Kabbalah Centre are the worst kind of frauds. They may teach many things, but actual Kabbalah is not among them, and their practices are willfully ignorant, disrespectful to the tradition, deceitful, and avaricious. They prey upon the ignorant, the unwary, and the helpless. They take the holy and sacred Name of God and debase it by selling it as simony. In their stores are the parchments made to be put inside mezuzot (the little cylinders or boxes you see affixed to the doorposts of Jewish homes and businesses): these must be handwritten, perfectly and without error. Those in the Centre shops, sold as "amulets" are often sold, as their clerks say, with special words of power and protection written on the side or back: anyone with good Hebrew knows that the "special words of power and protection" mean "unfit for use." They sell holy water. Judaism has no holy water. Water cannot be blessed or cursed, according to Kabbalah. They told one of their "congregants" who had cancer that bathing in their holy water would cure him. He had to purchase close to a thousand cases of their bottled holy water (at $5/bottle) to fill a small pool of the "requisite size" for him to immerse in: he gave them tens of thousands of dollars for their blessing cure. They gave him water, and he died. They tell people that they have no need to learn Aramaic or Hebrew to learn the book Zohar (the central text they claim to use)-- that one need not really understand the words, just pass one's finger over the text, and it will magically imbue one with good energy. They "suggest" that it is best to use their edition of the Zohar, which costs between $250-$425 dollars, when anyone could purchase a perfectly good edition of Zohar in any decent Jewish bookstore for less than $100. They sell all manner of amulets and talismans for exorbitant prices, with little proof of efficacy. And they teach that the Kabbalah itself strips the learner of any need to practice the full range of the traditions and commandments. I don't care who their practitioners or congregants or adherents are, non-Jews or Jews, I don't believe it is acceptable for anyone to support them. They are everything that Kabbalists should not be, and exemplify the worst sorts of perversion of religion. It's people like them that make me regret I don't believe in Gehinnom (Hell), because they should only go burn there...if there were one...which I don't think there is. I spit in front of their headquarters whenever I pass it. They have nothing to do with real Kabbalah or real Judaism. And if Madonna thinks otherwise, the more fool she.

__________________
Dull sublunary lovers love,
Whose soul is sense, cannot admit
Absence, because it doth remove
That thing which elemented it.

(From "A Valediction: Forbidding Mourning" by John Donne)