Because threateting with war to knock out nukes is one thing, and to threaten -as Iran does- "to extirpate the zionist entity (Israel) as the cancerous tumor of the Middle East" is threat of genocide, with nuclear means. That's quite another. BTW, I am sure Iran has tried many, many times to murder Israelis. And through its proxies Hamas and Islamic Jihad, it has murdered them with suicide-bombings by the hundreds, mutilating thousands. Then there is Iran's anti-Semitic bombings in 1994 on Argentina's AMIA relief agency; the Israeli embassy was car-bombed in 1992 murdering more Israelis. It's Hezballah proxies have murdered US and French Marines by the hundreds in Lebanon. I could go on, but the bloodtrail goes to the one regime in the entire world, who threatens to wipe out just one particular country, Israel, from existance. That includes all its children, babies, women, men, elderly people, its cultural, social, scientific life; its museums and cinemateques, its entire civilization. So the answer to your question is a resounding no. Besides, prove first Israel was behind today's assassination, as opposed to the CIA, the MI6 or the French or German intel.
World Jewish Congress: Nazi train treasures must go to rightful owners (Reuters)