The Iranian nuclear agreement was negotiated between  Iran and the P5+1 (the permanent members of the United Nations Security Council—the United States, the United Kingdom, Russia, France, and China—plus Germany) and the European Union. 

Sensible leaders of largely sensible countries.  Not the kind who pretend you can write off and abuse an entire nation and its people as eeeeeevil.  Booga booga.  In other words as well, the deal was NOT negotiated by the likes of Trump and Netanyahu.

Iran supports Hezbollah like Saudi Arabia supports ISIS or the US supports the CIA.  See the problem?