Sir, you have been selected for a "random" additional security check. The Dutch, in particular, find it highly suspicious that an American like me should speak fluent Dutch without ever having lived in the Netherlands. The fact that five million Dutch citizens speak fluent English without ever having lived in England or the USA apparently doesn't matter. My wife, who is a tall blond German, never is harassed like that--except in the USA. Of all people, the last American immigration officer to harass her at the Atlanta airport was himself an immigrant from either Surinam or the Netherlands Antilles: Dutch nameplate, Dutch/Caribbean accent and all--the last guy you would have thought would harass someone coming into the USA.
His problem with my wife? Her fingerprints didn't match what he claimed he saw on his screen. We protested that she was showing him the same fingers she had on her hand the last time she entered the USA. Nope, he wasn't having any of it. He tossed her passport into a special pouch and led her/us (I went with her, of course) into a detention area. Maybe he himself had been profiled going into Germany, and this was revenge, who knows? After about an hour, she was called in front of a supervisory board who reviews detainees, and decides if they warrant further attention, or if the reason for their initial detention was not justified. The head guy looked through her passport and asked what the problem was. We explained that the guy who had led her/us to detention thought her fingerprints didn't match the last fingerprints she had when she entered the USA. He rolled his eyes, apologized, and let her go. It still wasn't pleasant.