That could very well be.
I'm not advocating anything, more like I'm trying to see a logical (?) end point to this crisis. Whether its good or bad, one which you seem to think is bad. I would also add that assertiveness does not need to be violent or forceful, like mass deportations. But simply asserting European values, hardening laws, reducing migration, much stronger integration policies that are spread over a longer period with a smaller pool on incoming migrants, eliminating or reducing certain benefits. I freely admit though, that some policies could be a fine line that could easily be crossed into the dark side. Ultimately, I just want someone to talk about these issues and figure them out, aside from ever expanding and more radical individuals.
Unlike most people on this board, I think the hyperbolic statements made of current right wing parties in Europe, are mostly fearmongering. It can get much worse. Think of the most "extreme" party in the current EU and times by ten if you want to see a true return of something that looks like the past Nazi's. But I feel like that is what it's building up too (over decades of course). This is part of the question I posed as how far could that "assertiveness" could go.
Putting aside enforcing European values, which can mean a lot of things, I don't see hardening laws, reduced migration and elimination of benefits as good things either. At best they should be considered lesser evils. Hardening laws has a proven effect of being contra-productive to rehablitiation and being ostracising, as we can see in the US, for instance, especially with the War on Drugs (I'm European for the record, but it's a good example). Fewer immigrants will mean more refugees stuck in camps in countries that can't possibly care for all of them, like Lebanon that now has more refugees than Lebanese. This will hurt people who have a genuine need of sanctuary. Reducing benefits will obviously hurt the people who need them - the people who were the reason we instated these benefits in the first place. And that's the unavoidable effects, let alone the dark side you mentioned, the one we'll reach if we start implementing such measures discriminatingly (something that's already underway in many countries).
I agree that the current far right in Europe appears tempered and busy with fearmongering on the outside. That's because they're recruiting and can't get away with what they'd really want to do. But I've spent the better part of the last decade keeping an eye on the European far right and let me tell you, these are the kind of people who would gladly turn Nazi if they could. That's because in a lot of cases, they already are. A lot of them started their careers in Neo-Nazi organisations. Being Swedish I've kept a particular eye on the Sweden Democrats and their supporters. These days they look downright respectable, all trimmed and dressed in tailored suits. But 20 years ago - when the current leadership joined - they were still marching in SS uniforms. After the time I've spent on their blogs and their forums, engaging with them, I don't believe for a second that they've changed. Oh no, the people I've encountered are more likely to long for a future race war than fear it. I wouldn't say they need decades either, it took the actually Nazis less than 10 years to move from being imprisoned for treason to basically commanding all of Germany. When the environment is right, movements like these grow explosively. Suffice to say, I'm extremely concerned for the future of Europe based on this. I more or less expect a new Berlin Wall to run across southern Europe in a few decades, complete with land mines and machine guns, based on current developments - but it could also get much, much worse.
But back to solutions. If you ask me, I don't see any reason to make dramatic changes. Of course there's going to be some early turmoil but that's to be expected in the worst refugee crisis since WWII. Some people with ill intent will sneak in, others will be psychologically damaged and cause trouble because of that. But the vast majority of people are not like them. They just want to start over, to get on with their lives. Of course, to deal with the problems like what happened in Köln we need to actually give police forces and other services the resources they need, it's as absurd to ignore that there will be troublemakers as there is to claim that they're all damaged goods. Laws must be enforced. In other areas, we need to increase funding for essentials such as health care and housing - this should be obvious, more people means more costs. But I'm starting to think that I'm the naive one, and that Europe in general is more likely to start gunning down refugees and sinking boats than even risk a small decrease in our material standards. The complete clusterfuck that has been our response would suggest that. So who the hell knows what the right thing to do is. Sure, we could enforce our borders (which would probably require the New Berlin Wall I mentioned) and cling on to the status quo with the old, far too small quotas. But that would come at the cost of thousands of lives in refugees that have nowhere left to turn (because the rest of the world would likely follow suit too) and be a severe infringement on human rights. Not to mention that it would almost certainly embolden the far right parties, who would now turn their eye to getting rid of the people who are already here.
Even in a thread about migrant rapes in Germany, people have to drag in African-American/black people and talk about slavery. You can make your point without doing that. Natural's Law in effect again.
Also, why wouldn't they extrapolate the behaviors of the few to the many? That's human history as well. Do you honestly think the vast majority of these migrants aren't coming from countries where women's rights are severely repressed? I'm not saying the vast majority are criminals, nor will the vast majority commit these kinds of crime. But you're definitely going to see a clash of cultures as up to 1 million migrants who are uneducated, don't understand the rules, languages, norms of the country struggle to adapt. It's why ethnic slums get created.
If someone is going to use such an old and tired argument as suggesting that some ethnicities are too primitive for an open society (which claiming that the Middle East can only be ruled by dictators very much is) than I think it perfectly apt to point out just how old it is and the context in which it has been used before.
As for extrapolation, ever heard why generalisation is a bad idea? Because it oversimplifies things to a dangerous extent. This is especially true when you take the acts of a tiny minority of criminals and extend to a much larger group based on nothing but ethnicity (and vague allusions to culture, as if the entire Middle East and other places where the refugees come from share the same monolithic culture). Are you seriously going to argue that it's a good idea? A clash of cultures is of course unavoidable but the alternative, leaving these people to die or to waste away in overcrowded refugee camps, is far worse. As for your slums, you might want to look up the history of why they were created. Generally speaking it has nothing to do with culture clash - it has everything to do with the minority living in them not being allowed to live anywhere else, either overtly or through mechanisms such as not being able to afford any other place to live, or waiting lines that basically need you to start waiting in them for years to get an apartment in a nicer area (this is not an exaggeration, the average in Stockholm is 3-6 years for any apartment, longer for the more attractive ones - this is why almost all recent immigrants live in suburbs)
EDIT: And now I've done what I told myself to stop doing a few pages back; dragged the thread off topic by discussing the crisis in general. And with a wall of text too. I really can't seem to be able to help myself, guess it's time for another break from the subject.