It can be very hard to tell them apart until they act.
		
		
	 
Simplify.  Call terrorists extremists.  Do it for all flavors including  KKK, IRA, Boko haram or whatever, depressed taking arms and acting out, etc.  Now we can forget about religion and just concentrate on getting at the bad actors.  IMHO its time to get after those in Nevada stealing the people's grasslands.  Hi Ho Silver.
The problem of course is that people are lazy.  People'd rather demonize a group than track divergent attributes by act.  Perfectly natural.  Its the way of speciation which is the actual condition for which we are capable of adapting at generational rates.  Still, we need try  to refocus ourselves into more rational beings by societal mechanisms, or we'll slip back into identified tribes, balkanize to the extreme, and return to the bad old days of the cave ones.  
We can keep more than 300 faces in memory ferchrissake.  Leverage off that.