Fareed Zakaria, whose latest book Barack Obama was pictured reading, defines deviancy down: Islamic extremists are fine, as long as they aren't violent.
It's worth distinguishing between Islamists who are violent and those who are merely extreme.
Of course extremists can transform into violent terrorists or can certainly create an environment that engenders violence and that can also protect violent extremists. Hasn't Zakaria heard of the "broken windows" theory of crime prevention? Isn't extremism itself something worth preventing?