Do you have a source? It's described as using an antenna and a receiver, which is exactly how the naked scanners at the airport work: https://en.wikipedia.org/wiki/Millimeter_wave_scanner#Techni...
They may use different frequencies (airport scanners are in 24–30 GHz band) but it's the same technology.
That‘s why the devices in this article, unlike millimeter wave scanners, can‘t create an image of the scanned subjects. (and it’s also the reason why why millimeter wave scanners make very blurry images).
Instead, these detectors look for resonances in the emmitted spectrum.
The article was a bit light on details, but this description sounds very much like an old school metal detector, rather than an imaging device.
Radio frequency and microwave band emissions are strictly regulated, so if they want to sell these devices, they need to keep emissions below a limit, just like Wifi routers and Microwave ovens.
People have studied EM radiation for a very long time, and we know what‘s dangerous. Xray is dangerous, UV at high intensity is also dangerous, radio frequncy/micro wave is harmless (unless you go to really high intensities, but then you’d fry all electronics nearby)
Maybe check a physics textbook before you get all worked up.
Edit: Also, this technology is completely different and has absolutely nothing in common with millimeter wave scanners.