In my experience, as a mycologist, plant pathologists use common names for organism and the associated symptoms interchangeably. Even if they use symptom-derived names they are usually implicitly referring to a specific causal organism (or group of related causal organisms). In that sense these are just different categories of common names. On iNat the scientific name for the causal organim can be associated with multiple common names for the symptoms so I don’t see the issue.
A bigger issue for me is that the majority of disease causing fungi cannot be reliably identified from the symptoms alone. Yes some can, but by no means all. There should be direct evidence, usually photos of the causal organism, and often microscopy to confirm the cause. If a common name leads people to think that diseases can be reliably named from symptoms alone, then we have a problem. I see lots of identifications made on the basis of symptoms that I would not accept.
I touched on this when somebody recently asked about insect versus fungal damage.
https://forum.inaturalist.org/t/iding-plant-damage-insects-vs-fungus-vs/36303/6