AYFKM? Their clearly stated motive is to "wipe Israel off the face of
the earth"... They know damn well the west would never let Israel use
them as a first strike force, you know it, Israel knows it, Iran knows
it but it. Israel is not looking to "wipe" anyone off the face of the
earth, that's why so much of their weaponry is defensive....
There is no such thing as a defensive nuke
As a matter of fact, part of the planning to stop a Soviet Invasion of Europe through the Fulda Gap
included the use of defensive nukes to form barriers.