No, it's perfectly reasonable for items to be openly discussed in public after a certain amount of time. Not to mention I believe even her initial introduction in the movie is the visions Paul has, and this wasn't a twist at all, so it's hardly a spoiler.

You think it's reasonable for one of the few people that doesn't know how a half century old piece of media ends to stifle discussion for everyone else who does?

You might have a case for a new movie or show, but something that was public knowledge before the moon landing? Whose story has been repeating in our culture in various forms for six decades?

No, thats not a reasonable ask.