I would say the centuries of fragmentation of the Italian peninsula actually bolstered the nationalist spirit more than in countries with a long history as a unified nation (England, France, Spain…) and much literature taught at school treats this topic.
But yeah history doesn’t teach shit, it looks like…
I am Italian from a nearby place to Veneto: can confirm that there is an obnoxious cultural protectionism that’s appalling. In general people are very friendly and kind, but so close minded… I only grew out of it (I think?) once I moved abroad. It’s bittersweet, because it’s nice to be proud of being part of a community, but at the same time there is much emptiness in thinking of oneselves as something special just for what’s on the passport.