You don't cite a source for this claim, making me think it is an opinion.
This statement is a result of my informal yet many-years-long observations of psi community and psi debates (as well as many other communities and debates concerning similar
science-centered social conflicts (as I call them). And yes, this is not a strict formal scientific study.
But so is your observation, Andy. Do you have a scientific study to back your claims? I think not (if you do, a link would be precious).
Yet, unlike you, Andy, I - dare I be so prideful and boastful? ;) - much more open to the perspectives that differ from my own (without necessarily either agreeeing with them or liking them), and thus much less biased in my assessment.
So, according to my long-term informal assessment, "Left-wing" / "progressive" positions are at least as common - if not somewhat more common - among psi proponents as the "Right-wing" / "conservative" ones. It is true not only for parapsychology, but for other consciousness-related controversies as well, such as near-death studies, transpersonal psychology, energy medicine, antipsychiatry and critical psychiatry, and immaterialism in general. The same is true for anomalistics in the widest sense, such as ufology and cryptozoology. The exception, however, is the intelligent design (ID) debate, since most - but still not all - ID proponents are politically "Right-wing" / "conservative".
In this aspect mind-related controversies differ from the ones concerning "classic", not mind-related natural science, such as critique of the catastrophic anthropogenic global warming (CAGW) and modern environmentalism in general, where most contrarians are indeed "Right-wing" / "conservative". Again, there is also an exception - there are at least no less "Left-wing" / "progressive" critics of GMOs than "Right-wing" / "conservative" ones.
Some controversies are especially socially dangerous for the one who dare to study them in a non-hostile way, let alone defend contrarian positions. Two examples are the critique of safety and efficiacy of some vaccines, and doubt about a dominant HIV-AIDS causation theory. Treating each of them in any way, except a demonstratively pro-mainstream and aggressively anti-contrarian one, can easily lead anyone to treatment that may be desribed a a modern, and thus less physical - yet no less mentally tormenting and damaging - equivalent of public flogging, branding, tarring and feathering, followed by a life-long banishment. People who commit thought-crimes of such gravity essentially become socially dead for professional and academic circles in which they worked previously (as well as "respectable" society in general). In these controversies, contrarians may, again, be of any political persuation; it matters little, since after their intellectual "coming out" they will be exiled so far away from the mainstream that the very "Left-wing" / "progressive" vs. "Right-wing" / "conservative" dichotomy will start losing sense to them.