Conflating predictability with rationality appears to be a common failing amongst the supposedly sane.
Just look at the hysteria that flares up every time an event like this occurs. Guns are bad, gunmen are mad. Unless they're police or military, in which case they're obviously in perfect mental health and heroes to boot. Very rational.
Hasn't it always been that way? Human primates want to impress other human primates, so they get themselves titles. Doctor beats Master, Master beats Bachelor, Bachelor beats Drop-Out, Drop-Out beats Secondary School Graduate. Higher Education is part of a schooling system designed to perpetuate a stratified society. Graduating demonstrates agreement.
Just look at the hysteria that flares up every time an event like this occurs. Guns are bad, gunmen are mad. Unless they're police or military, in which case they're obviously in perfect mental health and heroes to boot. Very rational.