Some things I would like to add to this, as someone who shipped destiel when I came into the fandom-
When I joined the fandom in 2009, it was common knowledge that it was a reactionary ship of ‘oh thank God they aren’t related’ desperation. Like, it was openly discussed/laughed about/known within the largest destiel group on lj- I know; I was there. There was very much the acknowledgement of ‘yeah this show is amazing and we really wanted something to ship and some people ship wincest and that’s great for them but we’re all people who were personally squicked by that idea but then now there’s finally Cas and holy shit we can ship something and it’s marvelous’.
Know, accepted, acknowledged- because back in 2009 while there were of course ship wars there was not the 'my ship has the moral high ground and I must find reasons that all other ships shouldn’t exist because my ship must become canon and if it doesn’t the reason is shitty writing’ fervor that there is now. Back then, shipping was shipping and canon was canon and for most ships there was absolutely no expectation they would ever become canon and that was fine. We weren’t looking to 'win’; we were looking to have a good time.
When I joined Supernatural, I was squicked out by the concept of wincest. Fully supported other people shipping it, but I was like “eh that’s one of my few remaining boundaries fandom hasn’t eroded; it’s not going to be my thing’- and it wasn’t, for the better part of a year. I shipped destiel like mad- I spent hours every day in the destiel lj group; I would skip college classes to hang out with those people and scream over those two. I wrote thousands of words of fic- I wrote what is to this day the only “long” fic I’ve ever fully finished, and it was destiel. I learned so much about writing and about myself and I was wrapped up in a ship I adored and I was having an AMAZING time- but the thing was, my favorite part of the show was still the epic love story of SamandDean. Platonic love story, but still, it’s a love story. It was and is the heart of Supernatural- it’s why I watched, and why it will forever be my favorite story of all time. They love each other beyond sense or reason and it was, for me, utterly transforming and healing to watch.
But around mid season 5, I started to see a change in the destiel fandom. Sam bashing was increasing exponentially every week, and he was beginning to be written very badly/as a 'villain’ in lots of destiel fics. It got to the point I was having to click out of most of the ones I opened out of disgust because of untagged OOC Sam/Sam hate. It was spreading and spreading, and I was sick of not being able to read fics that included the best part of the show- and that’s how I ended up tentatively reading a couple of wincest fics and realizing that oh, there he was still being written in character. There he was being treated fairly, even when he fucked up- and Dean, too.
I continued to write destiel for several months, but the writing was really on the wall. The community was changing to become more and more anti-Sam all the time, and I didn’t feel comfortable there anymore- so I kept in contact with several friends I’d made, and I shuffled myself over to wincest- and no one was incensed by that. There was no she’s become a witch; burn her it was just 'well shit we’ll miss your stories, but we get it’- and for a while, it was like that. Lots of Sam bashing, but largely still a “normal” fandom situation-
And then destiel started to increase in popularity even more, and new people started being encouraged to just fucking skip or skim the first three seasons- aka the best and most critical part of the show in many original fans’ opinions. I literally have a friend that thought the show was just about Dean and Cas based on what she saw on tumblr before she watched the show. The perspective started becoming egregiously warped- hey watch this show, but skip the whole foundation, and don’t worry about one of the brothers, you only need to worry about this one brother and this other side character who was never meant to last past season 5- and then we started to have the rise of the antis, and people started clamoring that destiel would 'have’ to become canon, and they started pushing Jensen to talk about it at cons- even though he was extremely uncomfortable with that and had said that many times, and it wasn’t about shipping because he and Jared had openly talked about wincest at cons many times. It was the situation; it was the harassment. It was the fact that people were pushily demanding a fan ship be acknowledged in canon, and equating it to real life discrimination if it wasn’t. It was absolutely buck wild, and it only got worse. I love Misha, but he fed and fed and fed the madness until eventually he got a taste of how it all turned on him after he was like “I pushed to get this confession included; I thought you’d be happy”- not realizing that the fandom had ramped up to a point of escalation where they were never going to be happy with anything but full on canon, which was never going to happen. They had lost the plot completely- where subtext used to be celebrated and screeched over, it was now being tied together with a lot of red string by people in entire tinfoil body suits, screaming at the top of their lungs.
There is so much subtext to see with destiel. There’s plenty of text to see- but as a romantic ship, it is not canon, and it was never gonna be- and when it started, everyone involved knew that. It breaks my heart that that the joy of destiel as a ship got lost so completely under all the madness- because it’s a marvelous ship, when you just look at the ship.
Wincest is also a marvelous ship- and yes, the end was, in a way, a 'win’ for wincest- because the story returned to being what it had been all along, the epic love story of SamandDean- but within the confines of the show, that love is entirely platonic. Wincest fans know that. We love that. The show went back to its heart and soul- and that isn’t a romantic ship, and we’re more than good with that. That’s how it should be. Like Dean says- what’s dead should stay dead, and sometimes a fan ship should stay a fan ship. Sometimes they sail off into the sunset and become canon and that’s lovely, but you aren’t owed a canon ship just because you love it, or because it would be good representation, or because you have a whole corkboard of reasons why you believe in it. Representation is crucial; it matters deeply and it’s happening, but it’s not going to happen with every single ship you fall in love with- it won’t even happen for most of them. It won’t even happen for all of the ones that are cishet.