This is a quite interesting discussion. Economic downturns magnify social problems & nationalism. Fear of the foreigner, desire to return a country to its 'rightful' of place and being 'under attack', has led to hardliners gaining popularity (best historical example being the Nazi party, but also far right governments like Netanyahu in Israel, now partially the rhetoric of Trump, Le Pen in France). Obviously this leads to the possibility of war. Austerity also seems also to be leading to a change, popularizing mainly left leaning parties (Syriza, Podemos, UK's Labour).

Overall though, surely the roots of this migration issue lie in imperialism? Now we are seeing the long term effects of the petrodollar and geopolitical empire building. Look at the end of colonialism in the 19th & 20th centuries in Africa where it reached a point where local populations revolted and horrific civil wars ensued as a result of the inequality and brutality of the ruling regimes (Algeria, Angola etc etc), and then the further violence as tribal / ethnic groups battled for control of the liberated country, in the process renewing long standing religious / tribal feuds (often more brutal than the colonialists). This is repeating in the ME, Nth Africa (see what happened when Saddam, Iraq's secular ruler, was killed). The initial responses from religious hardliners had been building since the 90's, sparked on 9/11, set fire with the resulting payback / invasions and became a wild fire with the 08 crisis, which led to the Arab Spring.

I myself have no answers, it's a butterfly flaps its wings scenario. I don't blame anyone for trying to escape a warzone (Iraq, Syria, Afghanistan, Sudan, Yemen, Sri Lanka), a sanctioned or collapsing economy (Iran, Palestine, even Greece, Spain, Italy), an oppressive regime (Egypt, Saudi), a lawless land (Somalia, Libya). Idealistically, I support multiculturalism but realize that for every refugee / migrant that adapts to Western values there is one who tries to strictly emulate the rules and norms from his homeland. And then there may be an insidious one who migrates with evil intention. There is no singular recipe for successful integration.

And like TPTB mentions, idealism and fairness can be a Pandora's box. In an economic downturn the problems that come with large scale migration are magnified and could be the straw that breaks Europe's broke governments back. In the end, perhaps we all deserve it for paying more attention to reality TV, sports and fast food with our SUV's and massive houses instead of revolting against what is being done in the name of profit, lifestyle and 'God'.