A French Canadian decided he had enough of Islam and went into a mosque full of adult men guns blazing. He eventually felt sorry about what he did, called the cops, and turned himself in, instead of continuing the carnage in the midst of dozens of injured people he had the opportunity to finish off. A strange mixture of timidity and terrorism in this one, resulting in a very low score of a mere six dead. The Nice truck driver killed 84 French, so it's pretty clear that France's martial record since World War II remains as pathetic as ever.
Do I endorse this guy's behavior? The answer is a complicated no. I certainly endorse the death of every last Muslim on Earth. They have decided of their own free will to worship a God whose primary prophet was a rapist, mass murdering pedophile. Since they endorse Muhammed, they're all as bad as Muhammed was, which is about as bad as a human being can become.
But there are good ways and bad ways to go about this goal. The right way to lower the Muslim population to zero is to deport all Muslims from non-majority Muslim countries, squeeze them into their already overpopulated desert regions, and then cut off all trade with them until they renounce Islam. Under this system they would all quickly starve to death or convert. Since Muslims are genetically no worse than, say, Hispanics, once they've converted out of Islam I have no special animus towards them, and they could be left alive with no deleterious consequences to the world. (Though that's still no reason to allow them to immigrate here.)
The wrong way to lower the Muslims population to zero is to go on an individual killing spree (a really timid and weak one no less!), that creates no change in real life circumstances, but does discredit the right wing as lawless barbarians, while creating additional sympathy for more Muslims to come immigrating in in endless waves. By alienating the anti-Muslim voice and magnifying the pro-Muslim voice due to people's natural sympathy towards those who are randomly and arbitrarily targeted by violence, this Quebec dude killed six Muslims but allowed in six million more into Canada. Talk about shooting yourself in the foot.
If there were ever a time when killing Muslims simply for being Muslim was acceptable in society, it would be long after 100% of them were deported and therefore the problem was solved long ago. Any time before then, and you're just undermining the cause.
Violence should be the abode of the state, via consensus, meted out as justice. Unless the people affected by your vigilantism are also wanted by the state (like say, a bunch of criminals who raped your daughter), there's essentially no time an individual should ever take matters into his own hands.
If you could get 10% of the population together and they would all agree to kill 9 of their co-nationals who disagree with their utopia, including 10% of the military who would be in the perfect location and situation to kill 9 other soldiers in their midst, I would be fine with non-state violence. At that point I consider you a sufficiently developed state-within-a-state that your actions might actually bear fruit. I don't demand 51% consensus before the trigger is pulled, because it's rare for humans to ever be so sensible that 51% could see right from wrong. But I do demand enough of a consensus that your noble goals are magnified enough to even have a chance of success. Unless you're Superman, acting on your own isn't going to get you anywhere. In Canada, that means this guy needed to find 3.5 million friends before he went on this rampage. In America we'd need 32 million friends. If that isn't happening, it's time to give up the violent fantasies and go back to banzai cultivation or whatever. There's no point throwing your life away, or other peoples' lives away, or hindering the peaceful persuasion attempts of your compatriots towards undecideds, for nothing.