Why do you assume that? "Paranormal" just means "beyond normal," and "normal" is not all-encompassing; it merely refers to the usual and expected, by the standards of the definer. The Online Etymology Dictionary
defines the word to refer to "observed events or things
presumed to operate by natural laws but not conforming to those known or normal" (emphasis added). The earliest known uses of the word in the early 20th century (see the comments
here) were in journals of "psychical science" by people who considered themselves serious investigators of a phenomenon that was not understood but that they believed would be amenable to scientific explanation in time. So there's nothing in the word that implies anything beyond
all science and physics, merely what's currently understood or commonplace.
Thus, by human standards, all Q abilities would count as "paranormal," and could easily encompass control of things beyond human understanding, such as what we'd consider "ghosts." And arguably such things do exist in the Trek universe, e.g. disembodied consciousnesses or incorporeal intelligences. The evil pinwheel entity in "Day of the Dove" was essentially a malicious spirit haunting the
Enterprise, as was the energy creature in "Beyond the Farthest Star."
See, this is what laypeople don't get about science, and it's frustrating. Scientific thinking is
supposed to apply to things outside of science. That is literally the entire purpose of science -- to study things we
don't already understand. The whole blessed point of the exercise is to grow, to expand, to encompass new things.