Iran is singled out because it defies Washington http://www.veteranstoday.com/2011/07/05/jeremy-hammond-interview/

Iran is singled out because it defies Washington. Israel is the only country in the region that actually possesses nuclear weapons. Unlike Iran, it is not a member of the NPT. The Western media constantly repeats that Iran’s pursuit of nuclear weapons is a threat to the region, and that its nuclear program risks sparking a nuclear arms race in the Middle East. Israel’s nuclear weapons, for some inexplicable reason, do not threaten to spark a nuclear arms race.