Why Radio waves sit at the low-energy end of the electromagnetic spectrum, far below ultraviolet, X-rays and gamma rays. The energy in a single photon is nowhere near enough to knock an electron off an atom, so RF cannot ionize matter or break chemical bonds. That is why RF safety rules deal with heating of tissue, not with radiation damage to DNA. Alpha and gamma emissions come from radioactive decay, which is a completely different physical process.
Watch out Gamma and alpha are nuclear radiation from radioactive decay, and 'ionizing' describes the high-energy end of the spectrum starting around ultraviolet; RF exposure limits exist because of thermal heating, not ionization.
Radio photons are too weak to knock electrons loose: non-ionizing. The hazard is cooking, not ionizing.