For me it means "I like the idea of exploring these two (or more!) characters in a sexual or romantic relationship via fanworks." There's no expectation that the relationship be any definition of healthy, or value judgment on any creators or consumers if it isn't. But then again, I also don't expect fiction to explore only healthy situations or themes, and think there can be a lot of value in thoughtfully examining ones that aren't and how characters with XYZ characteristics would respond in such situations.