I've started to grow tired of the headcanon thing. It's already a bit iffy to try and declare an author's interpretation of their own work invalid because you don't want to believe it, but fans (surprise surprise, especially the ones on Tumblr) are starting to try and turn their headcanon into actual canon in their own view. They make their own interpretation, declare it official as far as they're concerned, and become upset when it's not true.
Take the Destiel fandom. Shipping Dean Winchester and Castiel is okay on its own, but a lot of Destiel shippers have been crying foul and claiming that the show is "queer baiting" for intentionally incorporating homoerotic subtext recently and not acting on it.
Guys, they're making fun of you. The writers are totally aware of the Destiel ship and how nutty its fanbase is, and are intentionally throwing in references to the ship to screw with the shippers. But the headcanon-loving fans don't get it because in their minds, Dean and Castiel are canonically in love and the writers are afraid to incorporate homosexual or bisexual protagonists.