This has kind of been addressed in the past:
- https://forum.inaturalist.org/t/create-taxon-field-functionality-analogous-to-observation-fields/7013
- https://forum.inaturalist.org/t/how-to-query-properties-of-species/6235
- https://forum.inaturalist.org/t/create-a-id-category-called-mangroves-that-captures-the-different-families-that-make-up-mangrove-species/6927/19
- https://forum.inaturalist.org/t/separate-lichen-and-fungi-into-two-categories/5212
- https://forum.inaturalist.org/t/if-something-looks-kind-of-seaweedy-is-there-a-safe-identification/4346
- https://forum.inaturalist.org/t/moths-not-a-search-option/8758
The upshot is that the way to do this for non-taxonomic categories would basically be to use the annotations or observation fields and work through those (the first link in the above list).
An issue with this is that many people never use the annotations or observation fields, limiting what would show up in searches.
Doing it any other way would require an unreasonable amount of time and effort by inat staff to manually go through and add non-taxonomic qualities to each and every species, and even if that was a viable option there would be disagreements on how certain organisms are categorized.