Again..there are no, and never have been any direct measurements of back radiation at ambient temperature any more than there have been photos of unicorns and dragons...none of them exist.
But plenty of measurements exist from a chilled receiver.
If your cult affiliation has driven you insane, you could claim all of the military's FLIR units don't actually work, because they're chilled as well, and therefore the images on them are all fraudulent. Those who have used such FLIR units, however, would rightfully call your claim insane.
Same goes for kooks who think other IR measurements don't count because the receiver is chilled. They're just astonishingly stupid people.
jc, have you officially jumped on SSDD's bandwagon of stupid?