I think I see a pattern here.
One of the accounts said he left a note asking for an autopsy of his brain, suspecting something was wrong. Turns out he did have a brain tumor; but research was not advanced at that point; no one thought much of it. The values of that day focused on the seriousness or criminality of the act, not the reasons or excuses of the perpetrator.
We need those values again. I have never understood excessive "mercy" towards violent felons because of mental defect or childhood trauma, without any corresponding cure for their condition.
If we are not prepared to defend a tolerant society against the onslaught of the intolerant, then the tolerant will be destroyed, and tolerance with them. —Karl PopperTolerance becomes a crime when applied to evil. —Thomas Mann