(I do not claim to be any kind of expert on this, so take with a grain of salt.)
My response was concerned about radio frequency (RF) waves, those in the 3 kilohertz to 300 gigahertz range. If there is enough power used to transmit the RF, and you’re close enough to the transmission, then you can get burned. Bear in mind that “close enough to the transmission” usually means “touching the antenna”. The devices that we commonly use like our phones, and the WiFi routers that support them do not generally put out enough energy to burn a person.
The electromagnetic spectrum encompasses much more than just radio waves, so I can’t really speak to the various risks of those wavelengths.