Out of sheer morbid curiosity, as an autist and a writer, things like this fascinate me. I like to know what not to do and how to avoid it where possible. That doesn't mean it's never happened to me, though, there's been a few times.
Now, I'm not talking about like gay characters in a show and you're not into that thing. I'm mean the media equivalent of receiving a great blowjob and then suddenly you get a finger in your ass that wasn't part of the original offer.
Mine is the show, The Magicians. I knew it would be lefty-leaning because that's just how the books were and the cast was diverse in hollywood's favorite way. That said, I was in for some trash and the fastforward button was for the parts I didn't like. 3 seasons in, I like the dumb plots and the sudden twists, then, the show decided to pull some stupid fucking meta and lecture the audience: Rasheed starts to lecture us that you're a racist, sexist, bigot if you don't watch/read something because the main character isn't white and male. After that, I completely skip a couple episodes, because fuck that bullshit. I calmed down and the first episode I watch, they killed the main fucking character, a white male. Series goes on, I do not. The whole fucking scene was the producers trying to guilt the audience into not rage-quitting the show by calling us bigots. After that, I decided I was never watching another syfyllis network show again, or one with a racially diverse cast, especially no Rasheeds.
He was part of upper class British establishment, was set to marry the sister of his 'lover', all upper class. There was no buggery on the high seas. He was driven by vengeance.
But the point was, he was the lead character and they turned him gay mid-way through the series.