The answer is that actually there are, because Hamas and Hezbollah both play political roles, very legitimate political roles, within their country. So it is not the case that this would be unprecedented.
With regard to your second question, about the actual evidence, there were very concrete cases and investigations. I'd be happy to provide that information to you after the fact. Certainly with regard to the direct involvement of Iranian and IRGC officials in the Argentinian terrorist attacks, that is very well documented.
As I said, I'd be happy to provide you with further information.