Whether or not the reputation is deserved I couldn't possibly say (the one thing I sent to Italy arrived), but I certainly agree that Italy's postal service has a very bad reputation. I know of a lot of eBay sellers who will either outright refuse to ship there, or require insurance on everything they send. It's very common to see a list of worldwide shipping rates divided up into Europe/Asia, etc. and Italy on its own with a rate twice that of any other.
Fair? I have no idea. But it is something that international buyers in Italy will have to contend with.