I actually think he said that Israel should be wiped off the map, not wiped out, there may or may not be a difference in meaning. My take on it would be that it should be regarded seriously by Israel and the United Nations.

As to Iran attacking Israel with either CB weapons, or with nuclear weapons at a later date. They wouldn't have to, they could do it annonymously by proxy through one of the terrorist organisations they support, that way they could claim to be not guilty of any wrong doing.

Oddly enough it was exactly that threat that Iraq under Saddam Hussein was perceived as being capable of in the post 9/11 threat evaluations.