i don't think it's a rule that Italians have big dicks. On many different countries you will find guys with very big, normal, or very small dicks. I'm pretty sure there are Italians with small or average sized dicks and this is the rule for all people no matter what country they're from. I've been with a Russian who was huge, i've also been with an American who was huge and the same with an Albanian. i don't think that all Americans Russians and Albanias have huge cocks, it's the same as somebody's nose for example. Some people have big noses some of them have small and some average sized. It's just how people are made, it's diversity. a penis is just a part of a human body, that comes in all shapes and sizes, just like a nose.
Of course statistically you will find a lot of big dicks on African men and very often small dicks on Chinese men but that doesn't mean it's a rule, i'm pretty sure there are African men with small dicks and Chinese with long ones.