Sunlight is ionizing radiation -- the ultraviolet light is capable of knocking electrons off their atoms, damaging nearby biological systems. 2.4 GHz radio wave

Sunlight is ionizing radiation -- the ultraviolet light is capable of knocking electrons off their atoms, damaging nearby biological systems. 2.4 GHz radio waves cannot do this; absorption just causes local heating (in this case, truly infinitesmal amounts). I dont know whether that meets the standard of convincing you, but it is fantastically well established science.