What about the people who haven't really been following news like that?
If they're exercising the personal responsibility (and good on 'em for that, really) to "purify" their first viewing experience to that extent, then they need to re-evaluate the lengths to which they need to go to keep that first viewing the purest. It's a matter of better managing whatever impulse control problems one might have, and deciding whether to accept that or double down even harder on curating the list of what outlets/communities you can visit.
If the studio itself is putting it out there, if the directors/writers are discussing it openly, and (to a lesser extent) if people who have seen the movie can cop to whether or not the characters mere existence doesn't necessitate a plot point in and of itself? It's not only not a spoiler, it's something the people involved with making the movie don't have a problem with you knowing. It's not going to affect the enjoyment of the film, in their eyes. It's information they actually WANT you to know. They're specifically putting it out there.
Whether you agree with them or not is a "me" thing, not a "rest of the world" thing, yunno?
Consideration is being thrown about in this conversation, and consideration is a key thing to keep in mind, definitely. But another thing to keep in mind is perspective, and I think what's annoying so many people is lack of both those things.
FOR EXAMPLE: I've read some Doctor Who scripts for season 8, and I've seen the workprint of the 1st episode. There is discussion going on in that thread regarding people's hopes & wishes for characterization in the new season. Now I COULD, if I wanted to, attempt to vaguely assuage some of those fears, and confirm some of those hopes. But out of consideration, I'm not even going to attempt being slick about it, because when you boil it down, what I'm trying to do is figure out a way to spoil without spoiling for the sake of the conversation. I'm trying to find a considerate way to be inconsiderate, essentially. So I'm just not going to bring it up or discuss it at all.
And what makes it easier to come to that decision is the knowledge that, at the end of the day, this is disposable entertainment that I have no financial or personal investment in creating. It's just a thing I consume, and in the case of TV, a thing I didn't even PAY to consume. It's just there. No matter how much fun/enjoyment I get out of Guardians, or Doctor Who, or Hannibal, whatever, it's still just a piece of fiction. It's not really that important. And since it's not really that important, it's not worth it to engage in behavior that I know is going to lead to a big, long, drawn-out, butt-clenching fight.
When people knee-jerk complain that an actor has been announced as appearing in a movie as a certain character, and their first thought is to attempt to shame the person who is trying to have a conversation about it, there's a lack of perspective in play, and combine that with any percieved lack of consideration, we're going to end up at this thread sooner rather than later.
Da fuck? Who thinks that?
I've had this pop up in previous "the Nature of Spoilers" conversations before.