There's a US parenting forum, which is very different to MN (it's completely anonymous and very fast-moving, which means you don't get these 1000 post threads and sagas going on - completely addictive in a different way), and they have a system whereby you can click "dislike" on a post, and after a certain amount of dislikes, the post is greyed out. It's still there, you can still read it, respond to it, but you get a heads-up that the post may be offensive/fake whatever.
What I like about it is the automation of it. There's no one sitting agonising about it or doing detective work behind the scenes, it's just a numbers thing. And I've never seen it trigger any sort of retaliative frenzy or agonizing about why it's been disliked.
MN works differently, I know, and I know there would be a behind-the-scenes process, but I think a greying-out style thing could work while they're looking into it. Otherwise, you have the situation as it stands, which is that during the time MNHQ are trying to get to the bottom of it, hundreds of posters are drawn in, some becoming emotionally invested and making themselves vulnerable.
"Educating people" is a waste of time, imo. You can tell them what you like, but as has been much discussed on this thread, people enjoy a dramatic thread and they want to be part of it. Others are just plain naive, or simply more trusting than the cynical among us. And some can relate to the story and have a personal, often painful connection, and they want to help.
I think some sort of gentle system to signal that the thread is being looked into might just make people stop and think a bit first.