I think that the problem stems from the fact that most people who do engage in this kind of behavior often confuse patriotism with blind nationalism. A person who is patriotic loves their country, but can still find faults or room for improvement. Because of their love for their country they strive to try and make their country more ideal in their eyes. A nationalist will have blind devotion to their country and take any criticism, even if it is from someone who is patriotic, as traitorous or treasonous. It's really quite sad because since 9/11 those lines between patriotism and nationalism have kind of gotten blurred.