It’s probably simply a matter being raised (and therefore being familiar) with a certain term. In Dutch and English, the languages I read and write most, they are called spaghetti westerns, so that’s the term I like and use most. Western all’italiana (the plural form of western is western in Italian, so without the s) is typically Italian (some Italians still see spaghetthi western as a derogatory term) and I like it. I somehow can’t get familiar with Italo Western, don’t know, doesn’t sound right to me. I think Macaroni western is used in Japanese. ‘Pasta’ is somtimes used by American critics (maybe Maltin introduced he term). I don’t dislike it, but don’t really like it either.