It's not just the Americans . I don't like to generalise , but I've found that Italians don't take the same tolerant attitude to alcohol consumption as the English Irish , Scots and Welsh do . The same to a lesser a degree applies to the French .They've got too much style is the explanation I've heard . It's got nothing to do with puritanism judging by Italian attitudes in other regards.
I'm not so sure about what they are like at home ,but from what I've seen of them ,Italians do not like to be seen drunk in public .Drunk women are particularly frowned on.