Since I used to read tales of Norse heroes as a boy, I know what a “nithing” is. But I doubt whether many people do these days.
How about “yellow dogs”?
A word like “nithings” could work, if it catches on. It’s almost a blank slate to most people, and so in the beginning it will be defined each time it is used in the context of those who employ it. It might remain off the radar of Islamofascists long enough for it to accumulate a common and easily communicable thought reaction for the first group that uses the word. Those who don’t want the Islamofascists defined accurately, those who would try to squelch us seeing them for what they are, could be caught off guard.