Because certain spiritual groups use “science” as a buzzword for selfish reasons. New Age groups, for example, have this tendency to take things out of their context and explain them through terms that came from another sphere of thought, like using “energy vortex” or “dimensional doors” to describe some phenomena in some tradition that focuses on self-cultivation. But of course, they take terms from Modern Physics and apply it willy-nilly to anything that strikes their fancy, without even studying either physics or the tradition they’re incorporating into the package they’re selling. So you can see why both scientists as well as traditional lineage-holders might raise their eyebrow when they hear of these things.
And unfortunately, there is hardly such a thing as objective science operating in some vacuum, with the sole mission to find Truth. As my professor in Anthropology said plainly, there are taboo topics which will cut your career short if you become associated with them. There are many good men and women at university, but just making one open-minded statement about a taboo topic can get them labelled as a pseudo-scientist on Wikipedia and elsewhere and that is just career suicide.
But how do you derive valid conclusions using a method built on premises that are contrary to the ones used in the tradition you are investigating? Basic problem in anthropology.
Michel Foucault’s concept of the épistémè already makes it clear that there are always a priori assumptions that drive each paradigm/age, which determine what is seen as possible and also what is acceptable in terms of proof. Thomas S. Kuhn’s The Structure of Scientific Revolutions is also good for putting things in perspective. Science is its own cultural product and consitutes a paradigm, whereas most of the older traditions that discuss things such as subtle energies or auras came from a different paradigm, which are naturally not compatible. The mistake most people make is that it does not mean that one paradigm supersedes the others, but unfortunately, there is often the implicit assumption that science has superseded all previous paradigms, which would mean that they all would have to justify their existence through scientific validation. And that is what you see happening around the world. For example, I did my work on Siddha Medicine and how it is currently practiced in Southern India, and they have unfortunately long ceased to continue on their original trajectory of research and experimentation, because the British outright banned it for the majority of their occupation there. Now they have been reduced to a state where they’re mostly busy doing empirical studies on what parts of their tradition can be scientifically proven. Ironically, their efficiency at healing people used to be better before this modern process was initiated because they did not have to deal with patients that were born locally, but have grown up with a Western materialist mindset because of globalization. Needless to say, the Indian government, just like the Chinese one, operate within the modern scientific paradigm and are practically hostile towards their own cultural traditions, which only get attention in so far as they can be turned into a part of the tourist industry. But I digress.
