I've got to disagree with Italians hating Americans.
My wife's family is in the Venice area and from what we've been told, except for the 'students' the majority of the country is very Pro-American.
The thing that most people (Americans) need to realize, is that when you are in another country, you can not and should not expect every one to bow down in your presence. It is completely obsurd to go to any country and expect them to speak English and know what you want from them. Take some time to learn some of their language and customs and it will be very helpful.
I do not know the laws in Italy but we usually travel Europe a few weeks every year and with a few exceptions, I've always found most items readily available. Try to stay away from the big tourist areas and places were the US has military bases, they are probably tougher in those locations.
BPP