I have briefly discussed the issue of antisemitism in Italy here, or the relations between racism and the antisemitic legislation and persecution of the Italian Jews here.

It is also - I believe - essential to keep in mind that Hitler wasn't merely an antisemite, but a man who had made antisemitism into a fundamental part of his social and political project. It is a very "high" standard to meet.

As to Mussolini, albeit he had no qualms with engaging in the kind of casual antisemitic remarks which were almost a staple of pseudo-intellectual bric-à-brac around the turn of the century (not that "true" intellectuals were above all that), he didn't appear to put much weight into those expressions, nor to take a significant interest in the "Jewish question" until the mid 1930s. His (relatively) numerous personal and political frequentations of Jewish origin did not appear to take issue with his attitude - like they did, instead, with the more openly antisemitic position of Farinacci, or Preziosi.

It should also be understood that Mussolini - when discussing issues such as "race", or "Jewishness", or "Slavic languages" for instance - tends to use those terms in a way which is as "imprecise" and ill-defined as his professional and political functions demanded (or allowed for), but which is also perfectly in line with the cultural trends of the period, where pseudo-scientific publications and serious and well regarded figures alike commonly employed a phraseology which left the door open to, when not openly encouraged, that sort of "eliminationist" discourse which was destined to find a concrete expression in a few decades.

Unfortunately, with this kind of ambiguity, it's not always easy to distinguish the "intent" behind the chosen words. That said, the more or less general consensus is that Mussolini wasn't especially antisemitic in his views, but made recourse to antisemitic tropes in the same way as many of his contemporaries who were either not alert, or - which would be the case of Mussolini - largely indifferent to the dangers of such language. And that only in the latest stages of the Regime's life, during the preparations for the occupation of Ethiopia, Mussolini begins to reconsider "racism" - and with that, antisemitism - as a viable path to accomplish that creation of a "new" Italian identity, necessary in his mind to secure and maintain the Italian "Empire", and therefore moves on to promote a racist and antisemitic legislation.

In additon to those linked, see also: Kallis, A. Genocide and Fascism: The Eliminationist Drive in Fascist Europe