The nomenclature used in the taxonomy of viruses is somewhat different to that of cellular organisms. The International Committee on Taxonomy of Viruses (ICTV; the authority on virus taxonomy and nomenclature; comparable to the ICN and ICZN in botany and zoology, respectively) states that all virus taxa are to be in italics, not just genera and species as is the case for cellular organisms. This is stated in section 3.30 of the ICTV Code. However, iNaturalist contravenes this rule and does not italicise any suprageneric viral taxa.
I believe presenting all nomenclature consistent with the accepted form is a goal to which iNaturalist should strive. This helps to reduce confusion with names and contributes towards iNaturalist’s reputation as a serious and reliable resource.