Checkmite
Skepticifimisticalationist
People seem to misunderstand psychology as if it were a hard science where you can find out whatever disorder they have based on testing. You can't hide high blood pressure from your doctor, but you can hide tons of disorders by simply not being truthful.
Oh yeah.
Watching the news, I see people talking about "red flags that were missed", but I don't see any. He was found to have this Asperger Syndrome, but he was being treated for it and taking his medicine. He was lucid, high-functioning, well-spoken, and in his own words perfectly capable of lying to defer suspicion. There was no obvious reason to think anyone should've "picked up" that this guy was a homicidal misogynist. A lot of people are saying that he "obviously had a serious mental illness", but the only things that apparently make that "obvious" are his killing spree and the manifesto which he didn't release until moments before his killing spree.
I think we might have to face the fact that sometimes there are no "red flags"; sometimes there's just absolutely no way to tell and nothing that can be done to find these folks out before they detonate.