Final answer:
Mussolini started as a revolutionary socialist but lost favor with the socialists after he abandoned socialism for nationalism and militarism, forming the Fascist Party. His suppression of opposition and elimination of socialist principles in favor of fascist ideology further alienated him from his socialist roots.
Step-by-step explanation:
Giovanni Giolitti did not lose favor with the socialists during the span of his political career as much as Benito Mussolini did. Mussolini started as a revolutionary socialist but then turned to nationalism and militarism after World War I. In contrast to Giolitti who was seen as politically moderate, Mussolini’s transformation and subsequent formation of the Fascist Party led to his appeal to nationalists and rejection by the socialists. The socialists favored Mussolini initially when he endorsed Italy's participation in World War I, hoping it would ignite a socialist revolution. It was his departure from socialism and move towards fascist ideology that led to Mussolini losing favor with the socialists.
Mussolini’s fascist regime suppressed opposition, removed fundamental political freedoms, and eliminated or jailed prior Italian socialists, creating a Italy that, while more stable, heavily undermined socialist principles. Mussolini's early support for the war made him appealing to Italian nationalists. These nationalists later formed the backbone of the fascist movement that would rise to power