How can the EU separate refugees from IS operatives???
They can't. At this stage we're probably flooded. There is literally zero border control.
The hordes push through and we just let them in. Why? Because it would be "racist" and "inhuman" to deny that to these "refugees". Nevermind the fact that they're nearly all coming from safe countries such as Turkey, so they cannot in any way be considered refugees fleeing a warzone at that stage.
If they wanted to apply for asylum, then they could've done so in our foreign embassies in Turkey and such. Instead, they just rush our borders or cross the sea in crappy little boats (and we often end up having to save them). They know European politicians are too spineless to do anything out of fear of, once again, being branded racist or inhuman. Wouldn't want anything like that to affect their reelection chances, would we?
What's worse is that our navies are actually towing any stranded boats to OUR coasts, instead of towing them back to their countries of origin. Everything we're doing is emboldening them and creating pull factors.
But perhaps what's most worrying is just how many Europeans are absolute fucking morons. Many people are actually welcoming this and want to take in even MORE of them. It's like they have no clue about how this is going to affect our cultures and demographics (which have already been tarnished in many places). Why? Partly because they want to give themselves a pat on the back for appearing 'progressive', and partly because these people are living in ivory towers. That is, in areas which have yet to be affected by mass immigration. Basically, this probably won't stop until half of Europe has been turned into a shithole and no one can ignore the issues anymore. But by then it will be too late.
The Germans, in particular, are the worst. They have a massive guilt complex. Being accused of "intolerance" (basically, Nazism) is the worst fate a German can suffer, as it will completely destroy their reputation and social circle. Other Germans will drop them like a hot potato and they will become a modern Leper. The Nazi accusation can be applied to any publicly announced opinion which is right-of-center on the political spectrum. In particular, it's the young 'progressive' individuals who always try to one-up each other in the Tolerance Olympics. There are pages and pages of shared media on facebook, glorifying the refugee situation and showcasing how awesome the Germans are for welcoming this 'cultural enrichment'. Those who don't like and share it are seen as suspicious. Those who try to argue logically in the comments are shouted down by the tolerance police.
This leads to a huge vacuum in the political landscape, because Merkel shaped her formerly conservative party to be a carbon copy of the Social Democrats. She rules with polls and automatically assumes the position of the perceived majority on any issue, meaning her formerly center-right party profile has completely vanished in the process. This leads to a huge, frustrated, center-right demographic (people who would vote Republican in the US) who have no party to vote for at all (except for the Bavarians, who have a conservative party of their own). The only other party on that side of the spectrum is the ACTUAL Nazi party (so to speak) and another independent party which recently got coopted by the real Nazis as well.
As you can see, the tolerance agenda is spread from the top. No politician can afford to mention something which isn't ideologically approved, because their political opponents will immediately call them out on it to profit from it. Merkel rules through maintaining the status quo as long as possible while spewing poll-supported majority opinions provided by advisers without tackling any real problems.