The thing you said that someone disagreed with was calling it ionizing radiation, which is a more general term and describes radiation with enough energy to ionize an atom or molecule, which means stripping off at least one of its electrons. That requires a lot less energy than activating nuclei in an element that is not radioactive to radioactivity. UV light and X-rays are both ionising radiation, but are not from radioactivity and cannot induce radioactivity.