sp1814 - like most of us, you look for a rational explanation to irrational behaviour, and the simple answer is - there isn't one.
This man is a ball of anger, confusion, fear, and general dislike of strangers, so it's not possible to understand why anyone would take the time and touble to source a toxic liquid and decant it into a bottle, all of which takes planning and forethought, purely with the intention of inflicting pain and distress on complete strangers.
It happens because in a complex society like ours, misfits xo-exist among us, and when they act in a particularly brutal and barbaric way, they make the news.
Sad.