That's a very disingenuous interpretation. I suspect a great many of those who have "used" psionics have done so because they have played Dark Sun*, and you can't play Dark Sun without psionics. It doesn't imply that they would want psionics in a setting other than Dark Sun.
*In my case, I haver played Dark Sun once. So I have used psionics. And even then, it was only the wild talents that all 2nd edition Dark Sun characters got. No one actually played a psion or other psionic based class.
Well it doesn't say that the 20% using it all the time only play darksun, I would rather guess that many of these are playing eberron kalashtar or are using psionics for their FR campaign.