Who defines what's a "terrorist" ? Were the IRA terrorists? Were the Red Brigade? Shining Path? Castro & Co.? The list could go on. Why is it OK for the West to fund their buddies, but no one else is allowed to?
19/20 hijackers were Saudi (and more recently, so was one of the San Bernardino shooters, for all practical purposes). UBL was Saudi. Please point out to me terrorists with similar profiles who are/were Iranian.
Iran's funding of Hezbollah can be legitimately seen as defending their own interests. Just like we fund scores of militias all over the region.