No. People viewed war as horrific long before the First World War. For example, Drew Gilpin Faust wrote an entire book (This Republic of Suffering) on how people coped with the horrors of the American Civil War. People have always known how bloody and devastating war can be but the First World War was the first war carried out on such an industrial scale.

Not quite, but interventionist intellectuals (such as Gabriele d'Annunzio) relentlessly campaigned in order to pass it off as a "glorious bloodbath" that could, and would, have regenerated the nation's decaying burgeois spirit and finally gotten rid of Austria - which they saw as Italy's natural enemy. Therefore, going to war was to them not only 'just and righteous', but also an auspicable thing.

This view was of course inspired and influenced by Futurism, an artistical/philosophical movement which exalted strength, speed, dynamism and modernity... curiously enough d'Annunzio and Marinetti (the founder of the aforementioned movement) hated each other, and G.d.A. actually called him "A phosphorescentous cretin!".