There are also other considerations when diverting to a 3rd country--for example, some people on the aircraft may have been denied entry to Italy (hard to imagine, but it's possible). For example, a passenger seeking asylum in France may have difficulty being admitted to Italy, or a passenger intending on transiting CDG to another country may have satisified transit requirements in France but would have been denied entry into Italy. In general, it's better to get somewhere inside the intended destination country to avoid these issues, and obviously AA saw fit to do that rather than deplane in MXP. Also, while I'm not familiar with AA's bargaining documents or FAA pilot rules, I do have a good friend that worked many years for another airline (and also did work with the AFA on behalf of her union), and while duty time and limits were well defined in that airline's FA CBA, there was also generous language surrounding IRROPS that gave the airline wider latitude during situations such as that above (at additional rates of pay, of course).