[So, let me insist, perhaps fruitlessly, that this is about e.g. my current weight loss attempts, and definitely not the coronavirus and various nonsense political garbage. It won't work, the application of this principle is too obvious, but let's try.]
I think there's a perception that people would be happier if they knew all true positive things, and remain largely ignorant of true negative things. Sure, for things you can't do anything about (note: a smaller category than you might guess), don't invite negativity into your life. But I think I disagree about whether I'd like to get bad news.
There was a time in my life where I hated checking mail – essentially only in college, when responsibility was new to me. Of course I would check the mail, but it would almost always be bad news, and I came to have this light background dread associated with it.
Until, of course, I had real responsibilities, and mail either didn't matter or alerted me to a thing I would hate more than anything to miss. Reading mail, I realized, was like polishing my armor. It's a bit boring, for bills or unexpected things, but if I want to protect what I care about, this is part of that process, and now I leave forwarding addresses when I move (and yes, of course I am embarrassed for my younger self).
Do you only want to get on the scale when you know you've lost weight? Do you only want to open the results of the blood test if they say you're okay? There was a time when I felt that way, and I could just say "but I've been an adult for a while now", but the flinch away from negative information isn't just a childish thing.
We all could be better listeners, and imagine things better. It's not a trivial task, trying to look at things and make the most accurate guesses you can. Everyone can improve. And I suspect, after people make a bit of progress, they just sort of assume it's a binary trait, instead of a skill.
Let's face the facts – together.