Welcome back to "Doggerel," where I ramble on about words and phrases that are misused, abused, or just plain meaningless.
The problem with this rhetorical question is that, irony of ironies, it's employed by people who have a habit of unnecessarily multiplying pluralities. In other words, they violate Occam's razor.
Take, for example, the topic of a psychic, like John Edward, who reportedly researches his victims before his sessions, and a woo who insists he's psychic. Which situation is more complicated?: The one where JE uses Google, obituaries, information-extracting accomplices, and cold reading techniques in addition to the previously stated hot reading ones, or that he uses psychic powers?
Well, if someone's directed you to this Doggerel in response to post or comment of yours, the answer may be surprising: The psychic power scenario is actually more complicated: We know that Google exists. We know that obituaries exist. We know that some people use accomplices to extract information. We know cold reading exists. (It's detailed in some stage magic books.) Any one of these may be able to suffice. Psychic powers are, at best, in dispute, and unnecessary to explain JE's performances.
That's why the tests like Randi's are important: Eliminate the known explanations, so that psychic explanations and the like become necessary to explain the results.
Of course, if psychic powers and other woo things do exist, it becomes necessary to explain why no one has been able to pass a genuine test using them. It also becomes necessary to explain why paranormal research has made zero progress.
All of this applies pretty equally to all woo: They all posit entities that would easily pass some tests, but such tests always end in failure, and are typically avoided. Whether it's the alleged link between thimerosal and autism or Bigfoot, they all have to explain the evasions and failures, often citing an even more absurd entity: A conspiracy of millions that works perfectly.