Some will become "Americanized" and some others might "grow into" the religion of their fathers - and add to the burden. Your friend might be fine now - will he still be eating bacon when he's forty? Maybe - maybe not. Americans are trusting - other cultures can see that as weakness to be exploited.
American cartoonists are learning to keep quiet. They're being actively intimidated by radical Muslims. It's ugly - it might be our future too.
Radical Muslims will use your friends - wittingly or not - as part of their "numbers" to get to a tipping point.
And that's the issue - can we totally shut down radical Muslims? Not unless we limit the number of Muslims allowed to immigrate here. At a certain tipping point, radicals shut down the moderates of that religion. Fear and intimidation are stock and trade. It's one of the things they're good at...
Young Germans ( even if they disagreed with Hitler) weren't allowed to live in the United States during World War II - for good reasons. Americans of German extract ( almost 20% of us) were not put them in camps - but we didn't open the borders, schools, and colleges for German youth to come here. We need to be fair, but not stupid. And yes, I would stand with my innocent Muslim neighbors if someone came after them for no other reason than being Muslim. I would do the same if someone went after Jews, or Christians, or blacks, or middle class white men for no other reason than being a member of that class. Same with people who attend tea parties.
But don't be too lulled - there's a reason Muslim cultures are violent, poor, and aggressive... and your friend has the seeds of those ideas in his head - they were given to him at his father's knees. You have also provided seeds for him. Only time will tell what grows - what soil the rest of us can prepare for your friend. My hope would be that your friend's seeds grow into love a freedom of expression, of religion, and of democratic choices.
Of course he’s Americanized, he was born here. And if your argument is that he MAY possibly become violent and turn terrorists ten years from now is just an ad hominem attack, no one knows for sure what they’ll be in the future, I could become a radical anti-government militant going around killing federal officers. I don’t think I will, government does have its place after all (under our heels of course) but my point is we can only assume the future to the best of our knowledge.
As for bringing more here you’re mostly right. But his father and grandfather were businessmen working with the US in Iran and they were forced to flee after the revolution. We do have allies in muslim areas, should we just leave them in the wind also.
BTW: the US not only transported to the US but gave citizenship to many Nazi Party members who killed Americans during the war. Oh, its alright cause people like Wernher von Braun somehow managed to live the rest of his life without turning any jews into his slave laborers. /sarc