I have seen this attitude countless times in Italy. Non si fa! (it isn't done). One does not include fish and cheese in the same dish. One does not even put fresh lemon on fresh fish. All this culinary Calvinism is especially amusing when you think of the quasi-anarchic nature of Italian society.
The author, one Tamar Adler, calls such people provincial, and I do too. Although the opposite extreme- anything goes (in which my fellow Americans often indulge) is probably even worse. As for me, I know that one of my favorite summertime recipes has zucchini and mint. You can find it here.
To further corroborate my view, I did a quick Google search of "pasta con menta." Results(s): 525,000, from standard Italian magazines and websites. Just on the first page there was quick pasta with lemon and mint, spaghetti with capers, tuna and mint (in the picture, from Barilla website), farfalle with mint, spaghetti with zucchini and mint, pasta with swordfish and mint, spaghetti with zucchini, guanciale and mint... Poor Signor Cavaliere!