What, precisely, was that "bellicose and very threatening language"? The original bill had a section declaring that it was the policy of the United States to "combat, contain, and roll back the violent activities and destabilizing influence inside Iraq of the Government of the Islamic Republic of Iran," utilizing "all instruments of United States national power in Iraq, including ... military instruments, with respect to the Government of the Islamic Republic of Iran."
Hillary rejected the bill because it explicitly allowed for the possibility of force against Iran. Her tough talk is just that -- talk. Her sanctions are backed by no threat of force; her diplomacy is no more valuable than a "Sex and the City"-style lunch meeting. Hillary is, in short, all bark and no bite.
Which explains just why her far-left support has yet to desert her -- she has not deserted them. Hillary is no stranger to manipulation; she speaks loudly (for the benefit of moderates and conservatives) and carries a small stick (for the benefit of the radical left). Rudy Giuliani has criticized Hillary for flip-flopping on Iran, but Hillary has never flip-flopped. She's a gung-ho opponent of a nuclear Iran, unless it means actually stopping Iran.