In this interview he makes the explicit claim that there are "too many mosques in this country." As The Politico notes,
Earlier, King had said in an interview with radio and television host Sean Hannity that 85 percent of the mosques in this country are controlled by "extremist leadership,"
When asked to clarify his comment to The Politico,
King did not revise his answer, saying “I think there has been a lack of full cooperation from too many people in the Muslim community.”
And of course claimed that the Politico took him "out of context" (which is why the full video interview was subsequently released. Judge for yourself.)
You know, it's fine if King thinks there are too many mosques in the US, actually. He doesn't have to like Islam, or muslims. It makes him a jafi, to be sure, but it's not any kind of insult to the muslim-American community. What is a genuine insult however is his assertion that muslim leaders have not been cooperative, or that the vast majority of mosques in the US are extremist.
This is analogous to the "muslims do not condemn" libel, which is easily refuted with even a cursory inquiry, yet still persists in the jafi worldview as an item of sacred dogma. The idea that the overwhelming majority of muslims the US are hostile and extremist flies in the face of common sense, let alone simple empirical reality. However, the Giuliani campaign clearly sees this as an axiomatic statement.