Islam has nothing to do with this whatsoever, no more than say a Christian shooter in some cinema in has anything to do with Christianity. Islam as a religion has a ton of issues that make this particular kind of thing very hard to get rid of and it is a sad coincidence that many youths that are easily misled are receptive to all sorts of bs but to generalize across a billion or so people because of what a few assholes did is simply wrong.
So the correlation is strong but a lack of tolerance will fuel the generation of more of these, not less.
The puppeteers are the ones that matter, the 'terrorists' are for the most part tools in the hands of masters at playing them believing they are making the world a better place (and how wrong they are).
I make no distinction between idiots of any plumage, be they muslim, Christians, atheists or something else, organized or acting alone. They're a plague on society and should be dealt with, preferably long before they can become a problem in such a way that becoming a problem never even enters their minds because they're too busy living and appreciating life.
I don't doubt it but those don't typically go around committing mass murder.
As far as the 'people are willing to kill and die for them' bit goes, that's a pretty good definition of insanity to me. After all if an idea was placed in your head and you then go out and use that idea as justification for murdering innocents that you have no personal grievance against (the one universal that most people seem to agree on is a bad thing) then there is something not entirely right in your head.
There seems a bit of wishful thinking there. We don't know the details but it seems quite likely Islam does have something to do with this.
So even if Islam is nominally involved and even if the fact that religious people have a fringe element (like all people!) that does not mean Islam is the cause of this. Just like Catholicism is not a religion centered around pederasty and just like atheists don't generally go around shooting people.
I recognize your username and I know you are highly intelligent, but how can you ignore all the daily evidence, crime statistics, the shows of intolerance + hatred + violence that Muslims put out towards the natives, all the logic and reason, and all the correlations about the Muslim population in Europe?
The Muslims that I know are very much upset about all this and fear for their future, if anybody is upset at the acts of terrorism by their nominal brethren it is them because they are confronted on a daily basis with the fall-out from all this. The scary bit is that the backlash against them drives them to become defensive and that's the one thing that should not happen.
There is much more to the story than fitting Muslims into the categories of: "non-terrorist" and "active-terrorist".
The fact still remains that Muslim [and other immigrating] populations in Europe negatively impact every single metric of social-ills (rapes, murders, acid-burning attacks, honor-killings / enormous housing and welfare costs / emergence of no-go zones / overall intolerance towards you / and so on and on).
This is the further split of society that you are talking about. It happens when you bring in incompatible groups into your home, and groups that do not reciprocate your good will, tolerance, and open mindedness.
It makes no difference that terrorists are few when double-digits (20%-90%) of Muslims (depending on region and % of population they make up) think that death should be the penalty for apostasy, that suicide bombings are justified, and so on.
You're forgetting a few not-so-juicy details. Most of these people that failed to integrate carry local passports and to the law they are just as French (or Dutch, or German or whatever) as the rest of the people living there.
As a rule all these countries practice freedom of religion so whatever the effect the immigrating (grand)parents had on the statistics of decades past the problem is the effects today. And you can't attack anybody on grounds of religion without opening up the traditional make-up of the country as well so that's right out because it would make a great many people in various power structures extremely nervous.
The failure then is to fail to fully integrate these people, part of the failure is theirs, part of the failure is ours.
The fact that the younger generation (and definitely not all of them!) are unable to get work, unable to find meaning in life and unable to get ahead no matter how hard they try creates a level of frustration that I can only imagine, but which broke through partially in the riots in France a couple of years ago.
As far as the 'double digits' are concerned, right now an ultra-rightwing party holds > 25% of the vote in NL, that doesn't make all the Dutch racists any more than 30% of the Muslims agreeing with some or all of the terrorist activities makes all of the Muslims supporters of terrorism.
It's each and every person as an individual that matters.
And if a person specifically supports these acts then you can go after them with whatever tools are available but until then there is no reason to act in a generalizing manner. That only makes the problem (potentially much) worse.
The human race has been based on groups/collectives since its inception. Even before we were Homo-sapiens, we were forming natural groups that defined us - with each group producing, collecting, and evolving individuals of similar attributes and behaviors.
Once you mismatch a group into another, some type of violence always arises.
And we are mismatching on a lot here -
https://www.youtube.com/watch?v=g0sRmpvdIIk
https://www.youtube.com/watch?v=b2nlIfn8tNA
In addition to the above, the recent floods of immigration into Europe is also not working because the groups that are coming in are largely doing so for the immediate benefits (ex: mindset that thinks welfare is "salary") and not because they recognize and respect European values.
The further this goes on, the worse it gets, and its becoming a disaster.
Muslims are in the West, much to your horror, and the reasons they are here just might have something to do with France's imperial past and present. But they're here: so what's your solution fella?
The same holds for fascists. Fascists terrorists are driven by their ideology, which in itself can be evil and wrong. That many adherents to an ideology are not violent is in itself not an indication of lack of evil. Even if there were billions of fascists, this wouldn't prove lack of evil of fascism.
The reason that people out of principle will not condemn Islam in western society is that is seen as 'another culture' and a 'minority' in the West. Both aspects are seen as a source for racism, which is bad. But therefore it seems hard to truly look at Islam as a possible source of evil. And I think it is.