I don't think so - quite the contrary, just look at the Beano's (a British comic) wartime strips - it's simply that like most of the things regarding our country's role in the war, such a subject has been never properly researched.

To give you an example, books such as John Hersey's "A Bell for Adano" do not quite offer a... flattering portrayal of Italians, who are mostly laid out in a rather patronising fashion as incompetent buffoons, cowards/war deserters or just backward people in dire need of 'civilisation'. All is made even more curious by the fact that the main character, Victor Joppolo, happens to be Italian-American yet he doesn't share any of these traits.

I would also suggest you to look at the Soldier's Guide to Sicily issued to Commonwealth troops at the time of the Allied invasion of the island; its description of the local Sicilians and their mores was quite disparaging (at best), not to mention borderline racist... at least by today's standards. Here's an excerpt:

"Sicily has a long and unhappy history that has left it primitive and undeveloped, with many relics of a highly civilised past. Saint’s Day feasts with their odd mixture of operatic songs and pantomime are a feature of the Island... the Sicilian lives on pasta with tomato sauce and a little meat, sardines, tunny fish, cheese or olive oil to add a variety of flavours; oranges, lemons, almonds are plentiful; Marsala wine, is the popular drink [...]

[...] Crime is highly organised in all grades of society; ‘gangsterism’ in the USA had its origins in Sicilian immigration. Morals are supercially very rigid, being based on the Catholic religion and Spanish etiquette of Bourbon times; they are, in fact, of a very low standard, particularly in agricultural areas. The Sicilian is still, however, well known for his extreme jealousy in so far as his womenfolk are concerned, and in a crisis still resorts to the dagger".

The full page can be found here. From our point of view, I believe that the British harboured far more hatred - and prejudice - towards their Italian counterparts than the Americans ever did. As to why, I don't know: I'm not an historian. Perhaps we weren't seen as enough of a threat? Given the relatively limited scope of our operations, that seems to be the case. And maybe, maybe the very fact that many Americans of Italian descent played a pivotal role in the war effort was reason enough for not wanting to alienate a significant portion of the troops/workforce.