"The few guys shooting up airports and nightclub, those are the people I would assume are the barbarians,"

I cannot speak for Dean but that was my assumption. It is not just a few.  Those that are sympathetic to the use of violence in the name of Islam are many . More so in Europe but with the large influx of Islamic immigration we will soon have the same issues that Britain, Brussels, France and the rest of Europe are currently having. 

While this is not the case with all of the followers of Islam, a majority do not hold the same values that westerners do, Sharia, subjugation of women, religious pluralism, tolerance of homosexuality etc. ( do not confuse tolerance with acceptance) We shouldn't allow those to emigrate to our country if they do not share our values. Otherwise we'll find our values in jeopardy. There is no reason a country should do that.