On May 9th 1915, the monument was christened for the 1,000 redshirts that accompanied Garibaldi on his trip to Sicily in 1860, beginning the 'liberation' of Southern Italy.
I put liberation in quotations because it soon became clear that the replacement of the Bourbon dynasty with that of Savoy didn't make that much of a difference to the Apulians, Sicilians and Calabrians. For decades the new Italian army was involved in putting down the ongoing revolt in the south, and banditism continued well into the 20th century.
The opening ceremony stood in the light of the Italian intervention in WWI at the side of the Entente. Italy had been allied to Germany and Austria-Hungary since 1882 but now opportunistically threw its weight on the other side, claiming not only the Trentino, Friuli and Triëste, but large parts of the Dalmatian coast in the secret treaty with Great Britain and France.
Gabriele d'Annunzio, Italy's most famous poet was recalled from Paris to whip up public fervour for war. France paid off his debts so he wouldn't be arrested.
On May 9th he promised, demanded bloody sacrifice: 'Blessed are the merciful, for they shall have splendid blood to wipe away, radiant pain to bind up'.
I'd think d'Annunzio got what he wanted. By 1918 over 670,000 Italians had lost their lives.