Funny, last time I went to the states they nearly refused to let me in because of an "Arab" stamp in my passport. Well I did fly Emirates, and I did have a free hotel in Dubai since it was a 9 hour stopover the first time.
Nearly refused, really? Or they just asked you about your last visited country, which is a routine question? (And if you filled in London for example and your passport shows entry for a day in Dubai, then it's common to ask about it.)