Earlier quoted context omitted.
Many people now feel patriotic to ideals than imaginary lines drawn thousands of years ago. It's an interesting shift, and in some ways was started by the US having a constitution (set of ideals) as it's foundation rather than a particular leader, king, or ruler.
Nationalism is a relatively modern phenomenon. The founding of the US was part of the rise of Nationalism. The idea that your nation (I assume you are american?) represents 'higher ideals' than others is rather nationalistic don't you think? From wikipedia: With the emergence of a public sphere and integrated economy in the 18th century, a broader sense of identification with one's country began to permeate society.…
How do the ancient Spartans not count as a prime example of nationalism? They had a very clear self-identity aligning with their nation.