I suspect the antipathy towards Psionics stems from some people's belief that FTL travel, gravitics and meson weapons may one day become possible, but telepathy never will.
It's okay if a machine can produce some inexplicable effect, such as hanging unsupported in the air, but not a human mind. Because humans who can generate the strange phenomena of clairvoyance / telekinesis / teleportation without a machine are, in fact, cheating somehow. Or, if not cheating, they're somehow "humans with powers," and you can't have humans with powers in hard SF, because again, it's cheating. Or it's fantasy.
And yet ostensibly hard SF books, movies and TV series have had people with telepathic or other psionic powers, from telekinetic phantom arms and Plateau eyes to mind melds, and nobody so much as blinks in those stories when they occur. Because what with the other strange wonders of their universes, from ringworlds to Kemplerer rosettes to double stars, to singing clouds and flying cities, a telepath is often the least freakish thing the universe can create.
And in universes where everything seems increasingly to focus on dehumanisation and mechanisation, the mass movement of (miniatures of) troops and machines, the clash of high end strategies and dirty tactics, and the boom and thump of HE rounds and the lightning crash of energy weapon discharges, Psion kind of brings it all back to the individual, and to the individual scale.