interesting as this again was done by a deeply disturbed individual, a paranoid schizophrenic. society since then has not gotten better at identifying threats coming from sick people. down to sandy hook, the completely insane individual is left alone until he/she commits an atrocity.
The other end of it is society starting to aggressively label and segregate people as "threats". Everyone would have to fit this set of behavior somebody else defined or else they get labeled as threats.