I finally gave up the ghost of pretending to watch when it became clear that the show was Serious Business and decided to be as angsty and melodramatic as a teenager's diary. But I definitely remember that the writers had noticed people liked Castiel and also noticed a lot of attention on him having HoYay with Dean and proceeded to play up that aspect in a nudge-nudge-wink-wink way. (And god forbid you even suggest toning him down from a regular because HE IS PART OF THE SHOW AND SO IMPORTANT)
So in some ways I can get why the ship exists in the first place, but not why they think it's canon and OWED TO THEM when it's so blatantly "we know you like us teasing so we'll keep teasing hahahaha j/k no homo" It's all a very strange circle-jerk and one reason why I hate when writers and producers involve the fans in their work somehow.