I don't know whether IONS is mainstream; it is not a university. It is at:
https://noetic.org/about/origins/
Rupert Sheldrake is certainly not mainstream, but he has earned quite a few academic qualifications:
https://www.sheldrake.org/about-rupert-sheldrake/biography
However, any organization that dares to mention parapsychology as worthy of study puts a target on its back. The people who imitate Randi will automatically label it as too far outside the mainstream to be taken seriously.
Parapsychology is not my field of academic credentials, so I will not be taking up the cudgels to defend it -- or Mitch Horowitz-- here. However, skepticism and logic are supposed to be within my bailiwick, so I ought to take up the cudgels against those who present illogic as logic and those who decry logic as illogic. Mitch Horowitz is not exactly a legendary logician, but Randi was a positively harmful influence on logic, so I feel justified in pointing out that Randi was a force for irrationality.
> ... Randi was a positively harmful influence on logic, so I feel justified in pointing out that Randi was a force for irrationality.
You mean, by posting a one million dollar paranormal challenge (https://en.wikipedia.org/wiki/One_Million_Dollar_Paranormal_...) that offered a million dollars to anyone who demonstrated a paranomal effect in scientifically valid laboratory conditions? And who opened the contest to over a thousand candidates, all of whom failed?
Sorry -- that's not how a scientist defines irrationality. In essence, Randi's challenge was, "Put up or shut up." A thousand put up, none succeeded, and since then they won't shut up -- which, in fairness, is their right. Meanwhile, no rational person misses the irony that the complainers produce everything but evidence.
In discussions about, for example, dark matter, personalities don't matter, because we have evidence. By contrast, in debates about the paranormal, personalities are everything, because of a perfect evidence vacuum.
Remember, when you bring up Randi, you're acknowledging a spectacular evidence vacuum. The greatest amount of scientific eminence is trumped by the smallest amount of scientific evidence.
>that's not how a scientist defines irrationality. ... >In discussions about, for example, dark matter,
I am delighted to hear that you are such an expert in how scientists define things. Can I safely assume your expertise in the history, philosophy, and practice of science is the result of graduating from one or more specialized programs? You don't have to share your own publication list -- I'm sure you have too many publications to mention here -- just tell me the basis of your academic authority and we can sort out the argument from there.