The conflicts of 1977 began with a student occupation at the University of Rome to protest education reforms. This quickly escalated into a fully-fledged guerrilla battle with the police on the streets of Rome. The conflicts spread to other Italian university towns and trade unions and political parties were also dragged into the conflict. After a student was killed during a demonstration in May, riots broke out.
This photo was taken by Paolo Pedrizzetti in Milan during the riots. It depicts a young man in a ski mask who was a member of a far-left organization who turned their guns against the police, killing officer Antonio Custra on May 14th ‘77. The image became synonymous with The Years of Lead and spoke of the culmination of years of struggle between neo-fascists and the radical left to control the political future of the Italian Republic.
Leftists didn't appeal to enough of the population to prevent fascism in Germany and Italy, probably because one of the major forces in left parties of the time was batshit insane "Let's wreck everything on orders from Moscow" factions.
Mussolini only performed his march on Rome after considerable electoral success, and with a strong right-wing majority already dominating parliament. Hitler was appointed by forming an alliance with the other right-wing party in Weimar Germany, giving them an actual elected majority.
You want to stop fascism? Street brawling isn't going to prevent them from worming their way into power with the consent of a considerable part of the population. You fight the fucking causes. You turn people to your side. Violence is notoriously ineffective at that.