You clearly didn't live in the '70s or early '80s Europe. I was born in '79 but the signs of political violence from those decades were all around me while growing up in Italy. That menace was somehow controllable through intelligence and surveillance, because it was mostly coherent; this wave is completely different. Intelligence will never catch bullied 18-year-olds and disenfranchised taxi-driver lunatics before they do something stupid. What you need is a stronger society where people are willing to talk to "differents" as much as to their own little tribes.