Take a look at the last 1000 years and you'll see one undeniable truth, when you mix different groups of people together there is always violence.  28 Christian were murdered in Egypt a couple days ago for no reason.  If me and my wife decided to take a trip to Iran and we went on a bus with out her having a head scarf how long would we live.  If we decided to go for a walk in Detroit intercity it's pretty likely we would be killed for being white.  It's not right by any means, but it is predicable.   I find it odd that so many people come to the US but then want to keep their own culture, language, and clothing.  Of course they have that right, but if they fully integrate in our society they would enjoy even more of what the US can offer (and get less unwanted attention).