IMHO, the fraction is that which is not radicalized. If Islamists were really moderate, there would be marching in the streets with protests signs against the jihadist terror cults of Al Qeida, Hezbollah, Hamas, Army of God, Islamic Jihad, etc., etc. I have yet to see any!
And while perhaps not all Islamists are terrorists, we know that all terrorists have been Islamists. I pray the world, led by America, marginalizes this gutter, slime, religious organization the same way we led the world in marginalizing Nazis.
Absolutely true.
However, that would be several thousand out of a billion-and-a-half.
Admittedly, there are probably only several thousand "moderates" among that billion-and-a-half, too.
But, then, there is the 95%-or-so who haven't made a decision yet, one way or the other.
What purpose is served by making all of them your enemy?
If most Muslims were jihadists, they'd already be blowing themselves up in the streets of our cities.