(Not for everyone, naturally. I know people who adore spoilers, and find them an exciting roadmap to what's ahead. I am just as likely to go "welp, that was the greatest hits version of the story, let's go enjoy something new.")
But saying "spoilers are bad" and "spoilers are wrong" seems very...I don't know, privileged? At least to me. I have friends who cannot watch rape. Cannot watch any threat of sexual violence. Cannot handle the use of date rape drugs or other such devices in fiction. I know people who are so severely afraid of spiders that even spiders in movies are not safe for them, or who can't deal with certain forms of bodily harm (eyeballs, sure, but no fingers, no teeth...). Most, if not all, of these people have really good reasons for their fears, and if they don't go around wearing shirts that list them off for your comprehension and enlightenment, that's because it's nobody else's business.
So they seek out spoilers. They look for them everywhere, because a little loss of surprise is worth it for the comfort of knowing a piece of media is safe. I was lucky enough to see Thor 2 early (I love you, Disneyland Annual Pass), and while I refused, for the most part, to be a source of spoilers, one person asked me a very basic "this thing will be triggery for me, does this thing happen" question, and got an answer. Because my desire not to put spoilers out into the world is not stronger than someone else's need for mental peace. I knew why she was asking. Refusing to answer at that point would have been policing someone else's choices, and saying I knew what she needed better than she did.
I will absolutely roll with "involuntary spoilers are bad": I don't want to get spoiled for everything in the universe the second I turn on my computer in the morning. I will roll with "there is a statute of limitations," and while we haven't all agreed on what it is, I stop getting grumpy after a week or so for minor things (it takes longer for big, shocking, "this changes everything" revelations). But we have to remember that for some people, spoilers are safety and self-defense. Spoilers are what makes it possible for them to enjoy media, just like everybody else.
Sometimes, providing spoilers is the only kind thing to do.