I'd love to know the source for that. Not saying you are wrong, I'd just love a source. Assuming you are correct, I think this is a case where clearly the law is allowing something that, by most western standards, would be considered morally and ethically wrong if not illegal.
How will this relate to the case under discussion? Probably not at all. I could see a couple of ways it could relate, however.
1. If AK and RS are convicted, and Italy applies for extradition, this could be used to highlight the "wrongness" of the Italian legal system by her supporters and legal team and make extradition politically untenable for a US judge. It is my opinion that if it got to that point, any extradition would have more to do with politics than law.
2. If this case angers Italians to the point that there is an overhaul of the Italian legal system, specifically the working of the Supreme Court. Who knows what this could mean to future appeals.