He's half right, more attacks would (further) radicalize Americans. However the object of their ire will not be their government, but rather radical Islam. How they would give vent to this ire remains to be seen, but I wouldn't want to be Mecca, Medina, Oom, etc, when the venting begins.
I don't think it would just be radical Islam. If the Michael Moores and Ward Churchills and Nick De Genovas and the rest of their Hate America First crowd ever get America the bloody defeats they wish on us, I would not be greatly surprised (or greatly saddened) to see them hanging from lamp posts in the subsequent weeks.