fandom is crap at categorizing gen fics so I can find the sort of gen stories I might want to read. If I have the source, I can find gen stories like the canon with my dvd player. If I just want a particular sort of story without a romantic relationship in it, I can often find a published book or short story to give me a story dealing with those themes or using those plot points, even if it's not a riff of a tv show. (And, hey, sometimes with media tie-ins, I can find the sort of story I want to read that is a riff on a tv show.)