He didn't "threaten to wipe Israel off the map", it was a mistranslation of a flowery metaphor, a way of speaking that is common in Farsi and I guess is easily manipulated by so-called "journalists" looking to further the government's agenda. It was more a criticism of Israel as a colonial state and stating that such a thing should not exist.
**UPDATE**
I feel like I shouldn't say this without citation so I tracked down the original article I read that described it:
http://thelede.blogs.nytimes.com/201...d-off-the-map/


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