EM radiation has a frequency of course. Wien’s Displacement Law links an emitting temperature to peak frequency. In that sense frequency indicates temperature of the emitting source, assuming it is spontaneous emission, not electrically generated emission such as radio broadcast waves etc. If you had read Johnson’s note then you would have understood what I was talking about.
Whether you choose to believe him or not, Claes is correct in saying that spontaneously emitted (blackbody) radiation will not be converted to thermal energy when it meets a surface which is (significantly) warmer than the source of the radiation.
You cannot refer me to any experiment which proves the contrary for spontaneous emission, now can you? I am not interested in the “politics” – only in empirical evidence – which cannot be forthcoming because it cannot happen. Backradiation does not add thermal energy to the surface.