Europe's seeing a wave of far right nationalism, and I've not seen a single middle-eastern fellow in these parties (admittedly, I don't go looking for them). Large parts of Europe are responsible for destabilising the middle-east. Large parts of Europe are responsible for carving up Africa, supporting brutal regimes run by dictators and exploiting the continent for economic gain simply because of having the stronger bargaining position. Of course they want to live in Europe. Your past governments (and some of your previous ones) have made where they live a miserable place. And no, don't pull the sunni vs shiite crap, it's only part of it. The British and the French trying to colonise the middle-east and all of North Africa, the topling of stable (if somewhat oppressive) governments because they wouldn't play nice. The tacit if not open support for illegal American tactical strikes. All of this stirs up hatred. The fact that they are now seeking a better life with their would-be assassins is actually rather tragic.
I know many of these people experience open hostility just living there. You expect them to move there, forget their upbringing, religion, favourite foods, language... essentially, who they are. Start talking in English, or French, or German... for some this is easier than others. Large parts of North Africa already speak French and English because of colonialism, but maybe they don't want to forget their culture just so they can avoid risking dysentry every time they are thirsty. Nor should they.
You know it's not just 'extremists' that get hate? It's all Muslims. Islamic women that choose to cover their bodies reciece routine discrimination. I'm positive islamic men do too, anybody vaguely middle-easten gets treated like a security threat unless proven not to be at any kind of security sensitive location. Not all of you do this, but a good percentage of you do.
I remember an hearing a group of young Australian refugee women talk about how frequently they get harrassed for being them. There was a headline earlier this week, 1/6 germans would join an anti-muslim march.
If this kind of behaviour is tolerated by so many, then I don't see why I shouldn't paint all of Europe with the same brush as the Golden Dawn or the National Front (France) the same way you apparently like to paint all Muslims as the just-got-back-from-syria-where-my-hareem-at kind.