Because I'm not inclined to believe in anything to begin with. I'm really not a spiritual person. I am quite interested in spirituality, but I don't live it myself. I can quite get the spirituality around music, (eg. the importance of music in part of Sufism), but there is not a personal belief attached to it. It's just.. interesting and understandable, I would say. (Although I obviously have random beliefs - like absolutely everyone has - because a whole lifetime is not enough to test even superficially every thing one learn day after day).
But I have no contempt or any negative feeling for those who are spiritual. As I said earlier, it's just that it's a different compartment than science, and for me there is zero overlapping (the idea being that if a belief is retrospectively proven reasonably likely/unlikely to be false (as the scientific method does not prove things to be right 100%), then it was not a belief to begin with. And that may be what you are pointing out. Anything can be tested with the scientific method, but it has to been done rigorously. For eg. one could examine one specific psychic event, carefully obtain all the info available, make hypotheses and test them (such things are actually done in several fields from psychology to neurochemestry). But, one cannot take several such events, before they are individually analyzed, and use them as proof to demonstrate that they are all linked and due to some general phenomenon. An analogy could be, taking all the deaths happening in a street to prove that the street itself is the cause of the deaths (when deaths are due to traffic accidents, heart attacks, violent crime etc). (In that case though, the street itself could also be dangerous due to bad urbanism etc. and actually influence some of the deaths. A more drastic version would be, trying to prove the street's NAME is the reason of all the deaths). In any case, this is nitpicking, the general idea I wanted to pass is that one cannot use a collection of unrelated events that most likely have different causes to try to prove a general theory. Sorry, it goes far beyond your original question - is actually pretty off topic- but I though that was something I could add).