I never shipped in HP because the romance side is not what interested me. As someone who writes, though, I had an interest - did I guess right? Heck, turned out I did guess out right. I guessed Ron/Hermione since book 2 [they were exactly what idiotics teenagers attracted to one another do, seriously, for that she got them right] and Harry/Ginny in book 5. I still think that she sucks at writing romance, period.
I don't ship often [Cloud/Tifa, Ichigo/Rukia mostly] mainly because I tend to mostly "support" silently pairings, or I am more interested in what their interactions will produce. Even in my shipping, I tend to be like that, not too much on the "and what if they had babies" [even though I write smut for the lulz] side. It's the interactions and how the pairing functions that interests me the most, and how they can make each other evolve. Not many pairings are really good - and nowadays, when I compare them to the Ichigo/Rukia interactions, I tend to think that I'm spoiled because they are that awesome to and for each other, so I'm kinda "yeah, main pairing is that, and...? XD
I tend to think that romance is usually a part of a story - be it big or tiny. The facts that fans go on about that is I think quite natural - may they want to fill the blank or to support the pairings they like, people are attracted to different kind of interactions. It generates both positive and negative things - I tend to think that fandom is a tiring thing - but yeah, it's nothing out of the ordinary. It just got bigger with the internets - before that, you could only talk about it with your friends, now it's instant all over the world. I heard that even back then, people complained about Little Women's ending haha.
The fact is that nowadays, I think that authors should be aware of this and become more cautious with the romance side. I think that Rowling is the perfect example of author who didn't give a damn about shipping, who had decided her pairings long ago and didn't try to weave them in the story, and ended her book the way she wanted with the pairings she first thought about, which resulted in the general assessment that she doesn't write romance well.