1. Many of the refugees are Christians, and there are no Arab Christian countries. In terms of finding a friendly church, America is probably their best bet. Most European countries are ultra-secular with an official established church and not much toleration for anything other than the official government religion. The only middle eastern country where Christians are not persecuted in Israel.
2. Many are losers in the “Arab Spring” which tried to establish western style democracy in the middle east, and failed miserably. There are no western-style democratic countries in the middle east for them to flee to. The only secular Muslim country in the middle east was Turkey, and they’ve turned politically Islamist. Lebanon is basically jumping from the frying pan into the fire.
3. Preventing terrorists from posing as refugees is a real problem but hardly one that is hard to surmount.