It is not true that we treat them like ****
Exhibit A:
https://en.wikipedia.org/wiki/French_ban_on_face_coveringExhibit B:
https://www.washingtonpost.com/news/worldviews/wp/2015/12/17/denmark-wants-to-seize-jewelry-from-refugees/Exhibit C:
https://en.wikipedia.org/wiki/Swiss_minaret_referendum,_2009Etc.
And this doesn't address the rise of UKIP (UK), PVV (Netherlands), AfD (Germany), National Front (France), DPP (Denmark), Jobbik (Hungary), etc in the political realms.
Europe has failed to properly exert control over its borders for decades, has taken on vast swaths of often-poorly screened immigrants, has experienced a relatively small social impact from a tiny minority of those immigrants, has in many places enacted laws and policies that are outright anti-immigrant, and now is looking at
immigration generally as the source its woes instead of seeing that European nations are the authors of their own misfortune on this issue. The problem isn't refugees, the problem isn't immigrants, the problem lies with a European Union that has failed to take any responsibility for management on both of these issues.
Even intra-European migration encounters this issue, though; one need only look at working-class opinion in the northerneastern UK toward Polish migrants, or continental European attitudes toward Roma to see that particular ugliness at work. It's not that other countries don't experience problems and policy challenges (see: 2015 Canadian election, CPC "barbaic practices" tipline; see also 2016 US election GOP primary), but there has been a particularly virulent form of ugliness brewing in Europe generally for the last couple decades that no one appears to be meaningfully addressing.
Europe has created in the EU a central government that should be responsible for continent-wide immigration policy - seeing as there are virtually no immigrant controls between EU members - yet has spectacularly failed to agree to give it any authority over its members on this issue. Again, the tide of refugees shouldn't have been met on Greek beaches with a sign saying "Hey, Germany is that way, mind the Hungarians, they're sticking numbers on people again" but by a coordinated effort from the EU itself to receive, organize, aid, and ultimately designate where refugees were to be initially sent after arrival. It should never have been on Greece, or Turkey, or any other individual member state to receive the flood, and yet it was, because nobody stepped up.