Together with them, after the Armistice with Italy (September 1943), he joined the partisan organization called Giustizia e Libertà, becoming the commander of its 10th Division, fighting together with US and British Armies against the nazi-fascists.
In 1971 he was amongst those who signed a document issued by the magazine L'Espresso against police chief Luigi Calabresi after the death of the anarchist Giuseppe Pinelli, soon after killed by a terrorist group of far-left named Lotta Continua.
He repeatedly took a critical stance against globalization, the foreign policy of U.S. oil corporations and the rise of right-wing political parties allied with Forza Italia led by Silvio Berlusconi.
When Bocca was an apprentice journalist, aged 19, he wrote an article denouncing what he called "Zionist imperialism" by paraphrasing the Protocols of the Elders of Zion for a local newspaper, La Sentinella delle Alpi.
In 1967, while covering the Six Day War, he wrote articles about what he described as the curious indifference he detected in Israel to the consequences of the army's occupation of the West Bank of ruling an Arab people.