Of course it was a regulation navy uniform (for both US - sort of - and Italians, especially for the Royal Navy[UK]). The claim was made that "shorts" were inappropriate for Dinner in Italy. I simply provied an example of shorts being appropriate. Certainly, were I wearing them to dinner in a Navy mess or wardroom, I would not hesitate to wear them to dinner "in town".
No more so than would I hesitate to wear "dressy" shorts to dinner at an upscale resturant in Taormina, Rapallo/Santa Margarita/Portofino or the Sestre Levante. The place suggests the "uniform".
As they say in Real Estate..."Location, location, location!"