I think the 'made in a sweat shop' part is a myth.
Pretty much all of the clothing worn in Italy is made in sweat shops. In fact, there is a town near Florence, Prato, which is full of Chinese owned sweatshops. That's probably repeated all over Italy **
Clothes sold in shops in Italy with 'made in Italy' labels are absurdly expensive and not especially high quality. A huge proportion of the populating are really struggling, especially in the south.
I will say though that Italians are very image conscious, as the saying goes, an Italian woman would go without food to buy a new handbag.
Specifically about club shirts - in my experience, it's common to see young people wearing the Italian shirt. During Internationals, there are flags everywhere!
** OFF TOPIC: . Two reasons for this I think: 1. they have sold off a lot of their industries to China, Germany etc. 2. They can't compete head-to-head due to having to price their goods in the over-valued Euro, rather than the Lira.
Actually, all of my post is probably off topic.