My apopogies. Is it your understanding that all scientific arguments can be made in a few words? I'll try...
From the Wiki article,
While terahertz radiation is emitted as part of the black body radiation from anything with temperatures greater than about 10 kelvin, this thermal emission is very weak.
Planck's constant tells us photon energy from frequency, very low for so long a wavelength/low frequency as sub-millimeter/THz photons. Light wavelength is in nanometers, still long relative to ionizing radiation.
Stefan-Boltzmann's constant tells us the power radiated by a perfect radiator at a particular absolute temperature, in this case call it 310K only 15K warmer than its 295K surroundings.
The imaging device, uses what it calls "passive imaging technology," so it is not a source. Where is the THz radiation source intense enough to be reflected and detected by an end user product, worse at a distance due to the effect of the inverse square law.
The device may work but not as advertised. All I had to do was see the word 'ray' and my BS detector tripped. Maybe detection of passively emitted RF is an explanatory analogy.
Halliday, Resnick and Walker are authors of one of the
freshman physics textbooks and the only one that I have room to keep. It is not advanced enough to even put "not even wrong" in context (there is a Wikipedia article on that too).