There is a lot of encouragement for everyone to be taking sides on a variety of issues at present. Human beings seem to have a variation on fight-or-flight that prompts them, when encountering a crisis, to either hide or take sides. In simple just-so stories of hunter-gatherer survival, it makes a sort of sense. I don't know if it actually is a superior go-forth-and-multiply strategy, but I can at least see how it could be so. In a sudden eruption of violence - or even a quieter struggle for power - the last thing one wants to do is be a close bystander looking unprotected and nervous. That's what hostages and examples are made from.
There are a few remote tribes whose members seem reflexively violent. Deep in the Amazon, on one of the Andaman Islands, in Papua New Guinea, in Dagestan, one finds such groups. But in general, most people in every group are not hairtrigger violent. Unless one is in a very small group surrounded by enemies, it's a bad survival strategy for everyone to be cutting throats at every approach. It makes trade difficult, for example.
At the moment, there is a back-and-forth between people who want to highlight the dangers of jihadists versus those who want to insist that most Muslims, especially in America, are decent folk. Both are true. Most of everyone are decent folk. Though Muslims, even in America but especially in Europe, have a higher percentage of violent people than, say Congregationalists. Or Jews. Or Buddhists. Not much way around the core belief of either POV, really. Just is. The difficulty comes when people want to claim further territory. Ooh, we're worried about backlash. Backlash is the real problem. Well, no it isn't. There is revenge vandalism of mosques in France and that's bad, but no one is, er, dead. Or from the other side, there are those who want to portray Islam as violent, root and branch, and would prefer that none of its adherents remain within our borders unless they specifically abjure violence. Many (though not all) of the other major immigrant groups to America couldn't have met that standard either.
Taking sides causes us to forget what we knew even two hours ago. When there was a mass shooting in Norway, one of my sons who lives there went on an anti-Muslim rant on Facebook, immediately accusing them. Another relative of mine was horrified, disapproving of such bigotry, and very quickly self-righteous about it. The latter had forgotten what he knew two hours earlier: a Muslim group had initially taken credit for the shootings. That was my son's context. OTOH, even in that context it was apparently pretty rank - he took it down and I only learned of it secondhand. A few hours later he was on to other aspects of Anders Breivik. Taking sides makes us stupid.
BTW, almost no one remembers that claim by the obscure Norwegian Muslim group now. I think I read it consisted of about seven people, who were hoping to become big wheels, and the followup is they didn't exist a year later.
People were quick to take sides about the shooting of Michael Brown. "You don't understand what black people..." Whoa. Whoa. This was a specific incident, with specific players and specific events contained in it. Same on the other side. "We support the police! They go out every day, risking their lives..." Well sure. But some policemen, and occasionally whole departments, are pricks. The fact that most aren't doesn't change the fact that some guys (and gals) are attracted to that job for bad reasons. I've met them. Hell, you've met them. Most black people, even in very bad neighborhoods, are decent folk who don't want any trouble. But they do have an unusually high percentage of violent, dangerous people. Just is. (Leave aside for the moment why that is. Many people pretend to know why, but have only a congenial narrative and no facts.)
The odd thing is that I am pointing out the almost stupidly obvious here, things that everyone knows, but we want to move off that ground to taking sides. We want to show our solidarity with oppressed black people or beleaguered police, or noble satirists, or offended Muslims. Jimmy Carter is sure it's all about the Palestinian conflict. Not that he's stuck in 1978 or anything. When all you have is a hammer, everything looks like a nail.
Which brings me to who we really should be worried about. With all the running around and taking sides, there is a surface conflict. That is absolutely normal human behavior, and not even very interesting, unless one happens to be near the violence. Watch instead for the powerful people quickly trying to turn this to their own advantage. The Front National in France is historically, deeply, anti-Jewish. They are now using the Charlie Hebdo situation to paint themselves as the Jews' best protector against these violent Islamists. I suppose it is possible that they have softened, deciding that Jews are the least of France's problem and better as an ally. But I doubt it. On the other side, Barack Obama is trying to turn the conversation to "violent extremism" in general, convening a conference in February to include educators, mental health professionals, religious leaders, and academics to discuss the problem. Let me predict five weeks in advance that the "violent extremists" are going to include people who aren't especially violent, but talk tough, and are on the opposite side of the political divide from Obama. It will be carefully titrated to use the fear of Muslim extremists in a different direction. Where the Republicans, especially the presidential hopefuls, go with this remains to be seen. That's likely to be convenient as well.
In both cases, Le Pen and Obama, I don't think it is a cynical manipulation. I think they believe it. Same for their opponents, in France and America. Having actual fear can be an excellent substitute for being a Machiavel.