You know what pisses me off about this kind of thing?
1.) It's an obvious marketing gimming like "ZOMG! THEY KILLED [insert major character who obviously is not dead and the only question is how they'll explain the character's inevitable return]!!!!!!" If it happens in story context, nobody cares. If they announce it, though, it generates headlines. It's all just stupid.
2.) It's tokenism of the worst sort. You're making a character gay to say you have a gay character. Stuff like this should either develop naturally in the story, or just be like a "Yeah, he's gay. So what?" They don't need to freakin' lampshade it every time it happens. There doesn't need to be a big "announcement" issue, or where there's some "moment" in which the big reveal happens.
The thing is, when we treat these kinds of things as "events" or as a "big deal," all it does is further the notion of "differentness" of gay folks.
And when you apply it to major established characters, well, that just makes it that much worse because then you can't separate the whole "This is stupid because it's commercial and because I liked the old character" from any sense of discrimination otherwise. If someone says "WTF?! Why'd they make Spider-Man a socialist?!" the response of "You're just a capitalist oppressive pig-dog!" Well, no, maybe I just don't like the fact that you're throwing a completely random turn into my beloved comic book purely to gin up headlines and outrage.
I mean, if they started a new character who also happened to be a socialist, great. Who cares? And the comics companies know this. Which is EXACTLY why they mess around with established heroes, and which is EXACTLY why whenever they do, it almost always ends up being a mistake that they later undo. "No, no, just kidding. Aquaman isn't black. That was actually just his cousin who took over for 8 issues." And it's not like anyone would object to a black aquatically based superhero. Nobody would CARE. What they care about is that the company mucked around with an ESTABLISHED superhero and changed them for the sake of tokenism, which, to my way of thinking, ought to be equally offensive all around.