When dealing with occult systems, there are actually entities involved, which not only the occultists recognize, but also Jewish Sages have always recognized (but do not respect, fear, or try to appease).
Taking people out of any of these systems means that you are removing a prime source of "food" from the tumah forces themselves, and they don’t like that, which, in my admittedly amateur opinion, is a huge part of the reason why otherwise friendly yoga practitioners treat the people who are pointing these things out with so much hostility.
At the same time, no one needs to fear this tumah, because Judaism automatically includes defenses and protections against these forces, such as Bedtime Shema, the daily Kriyat Shema, Pitum Haketoret (especially powerful against tumah forces), Perek Shira, Tehillim 91, Tikkun Haklali, hitbodedut, and so on.
One of my personal favorites is Pitum Haketoret, which is the recital of how the Incense was produced and offered and is found in every Orthodox prayer book. Formally, it is said once at the beginning of Shacharit, once more at the end of Shacharit, and yet again at Mincha. But even saying it once a day is very powerful.
How does it work?
Well, the burning the Ketoret mixture had a cleansing effect on the entire area of Jerusalem. All those unseen forces and effects of tumah that can affect one’s mental and spiritual health were basically blocked by the Ketoret.
Beyond its spiritual protection, reciting Ketoret also a segula for parnasa, health, and shalom bayit.
Daily Zohar explains:
[Ketoret] has the power to break klipot and remove negativity from our lives. It gives protection and can open channels of
Rabbi Shimon said in the Zohar that if people would understand the importance and value of this text, they would make it as a golden crown over their heads.
Here is also an excerpt from http://www.chabad.org/parshah/article_cdo/aid/2511/jewish/Ketoret.htm
The sublimation of evil is something that only the Ketoret can achieve, but this is not the sum of its purpose and function. The word Ketoret means “bonding”; the essence of the Ketoret is the pristine yearning of the soul of man to cleave to G‑d—a yearning that emanates from the innermost sanctum of the soul, and is thus free of all constraints and restraints, of all that inhibits and limits us when we relate to something with the more external elements of our being.
An important part of Ketoret is the inclusion of the foul-smelling chelbana (galbanum). Chelbana symbolizes the sinners. Rabbi Shlomo Ephraim of wrote in his Kli Yakar commentary on the Torah that just as the foul-smelling chelbana can be elevated within the Ketoret to offer a beautiful and cleansing aroma, so too can a sinner elevate himself or herself through teshuvah and have his or her foul deeds transformed into sweet repentance.
This page is worth reading in full:
But to give you some idea of what’s written there, I’ll extract several passages:
Rabbi Sutton writes about Vendyl Jones's discovery of a container of the Ketoret and how they received rabbinical permission to burn it with hydrochloric acid [and not with real fire]:
In 1994, the incense spices were presented to Rabbi Yehudah Getz of blessed memory, late Chief Rabbi of the Western Wall and Holy Places in Israel. A sample was also given to Rabbi Ovadiah Yoseph. Rabbi Ovadiah had his own chemist analyze the mixture to confirm its organic nature. Then both rabbis requested that Vendyl Jones "burn" some of the incense for scientific purposes (not with fire but with hydrochloric acid). At their suggestion, he had the spices combined together with the Sodom Salt and Karshina Lye which were also found stored separately in the cave in Qumran.
The results were astonishing. Although the spices had lost some of their potency over the two millennia since their burial, it was still powerful. The residue of its fragrance lingered in the vicinity for several days following the experiment. Several people present reported that their hair and clothing retained the aroma. More amazing, the area in which the spices were burned changed. It had been infested with a variety of flies, ants, moths and other insects. After the Qetoret was burned, no sign of these pests was seen for quite a while. This is reminiscent of the Mishnah in Avot (5:5) which states that there were no flies in the area of the Temple, nor was a snake or scorpion ever able to harm anyone anywhere in Jerusalem as long as the Temple stood.
And from the Arizal:
The incense consisted of ten spices or perfumes with good fragrances, and an eleventh spice, Chelbenah-galbanum, with a vile odor. These spices were each ground separately and then blended together to be used in the Temple. Since these eleven spices parallel the eleven Sefirot of the Universe of Tohu [Chaos], they are therefore said to represent the complete rectification of evil. This is indicated by the addition of the eleventh spice, Chelbenah-galbanum, which alludes to the elevation of evil back into the realm of the holy (Innerspace, Moznaim Publishers, 1991, p. 86).
And from Rabbi Aryeh Kaplan:
The Talmud (Shabbat 89a) teaches that Moses was taught the mystery of the incense by the Angel of Death. [The Angel of Death had revealed to Moses that the Qetoret has the power to nullify any evil decree, even that of death.] It is for this reason that when a plague broke out among the Israelites in the wilderness Moses ordered Aaron to walk through the camp with the incense. ["Aaron took the incense pan as Moses had commanded him... He offered the incense to atone for the people... and the plague was checked" (Numbers 17:12-13).] From here we see that the eleven perfumes have the power to overcome death and evil (Innerspace, p. 86).
But the Qetoret , in the very way it is made, and especially in the number and nature of its ingredients, has the power to overcome death and darkness, and completely transform all evil - in ourselves and in the world - into good.
Thus, the idea of transforming evil by elevating it back to its source in holiness is intimated in the incense.
And finally, that same article emphasizes Ketoret’s very important message:
It is important to point out here that this entire section of the morning prayer service in which the Qetoret is found (from the first blessings to the binding of Isaac, to the first declaration of the Unity, to the various offerings in the Temple) revolves around the ideas of retrieving, refining, extracting, and elevating the sparks of holiness and goodness, in ourselves and in the creation at large, from the unrefined state in which we originally received them.
(Again, it’s very worth reading the whole article.)
In conclusion, if you’re battling or have engaged with tumah in some way (intentionally or unintentionally), reciting Pitum Haketoret is a powerful way to both protect and cleanse yourself spiritually.