Perhaps the authors of the paper made the assumption that the reader would already be familiar with the effects of ionizing radiation on humans?
For example, this presentation by NASA (https://ccmc.gsfc.nasa.gov/RoR_WWW/SWREDI/2013/Evans-SWREDIB...) on Solar Energetic Particles (or SEPs) relates how one can translate from pfu (proton flux units which are used in the article linked) and biological effects as part of the solar storm intensity scale (slide 15).
Perhaps if someone was already familiar with the NASA research into SEPs, they would read this paper/article and say "Hmm, here is some evidence that Cosmic rays are not something that can be assumed to be negligible when evaluating radiation exposure risk."
For example, this presentation by NASA (https://ccmc.gsfc.nasa.gov/RoR_WWW/SWREDI/2013/Evans-SWREDIB...) on Solar Energetic Particles (or SEPs) relates how one can translate from pfu (proton flux units which are used in the article linked) and biological effects as part of the solar storm intensity scale (slide 15).
Perhaps if someone was already familiar with the NASA research into SEPs, they would read this paper/article and say "Hmm, here is some evidence that Cosmic rays are not something that can be assumed to be negligible when evaluating radiation exposure risk."