In both instances we can clearly understand the writer's position against said user being called out. Saying "/support" literally does nothing.
I understand what you're getting at, but with a statement like that, having a /support or "I support this" or "/nosupport" or "I don't support this" would help clarify their stance on the matter.
Without at least some statement or phrase saying their stance, their statement could be taken as a support or not, just a personal bias against the said user, or something else, it'd just up to the reader to determine for themselves and assume instead of a clarification so everyone would know exactly what their stance is
Imho I don't think there's anything wrong at all with using /support basically because it's just a shortened version of "I support this," and calling people "morons" for using it is just kinda petty, unless if their post was trash or contained nothing other than the phrase