I also often hear the mantra, "where's the evidence". By "evidence" it transpires they mean something repeatable in a lab and that anyone, even skeptics, can unerringly replicate. There appears to be no room in their worldview for spontaneous or capricious phenomena, nor where a certain psychological state is a crucial ingredient for the manifestation of the phenomenon of interest.
The fundamental point is this, if people assert something doesn't exist, they need to provide reasons for their belief. Not simply be content to say "prove me wrong". But I do not think it is an exaggeration to say I never actually hear any valid arguments. At best I am told that such phenomena, if they exist, are simply impossible, that it would break the laws of physics and even render the whole scientific enterprise as fundamentally wrong. But, we need to understand that the so-called "laws" of physics are simply a mathematical description of the patterns we find in the world. What these people are doing is reifying such a description and demanding that reality dances to its tune. In other words, they're putting the cart before the horse. However, reality has no obligation to conform to what we regard as "physical laws". Physical laws are general -- we lack compelling reasons to believe our current "laws" describe reality in its totality. In particular, they leave out consciousness in their description of reality. (I cover this issue in greater depth here, here, here and here.)
I think it's the power of our culture imposing its belief system on educated people. People just soak up the beliefs of their culture and their peers. We live in a scientism infatuated culture that fosters the view that physics provides a literal depiction of the ultimate nature of reality. Hence, all the qualitative features of reality -- that is, colours, smells, sounds and of course conscious experience itself -- are relegated to either being illusory, or are deemed to be translatable, without remainder, into the interactions of the ultimate entities that physics describes.
This is unfortunate. Ideally education should make people think. To question prevailing beliefs and "wisdom". Indeed, to be a sceptic in the original meaning of that word. There's precious few people who are rational intelligent independent thinkers. And I can't see that ever changing.