Ramesh, perhaps my original post lacked some needed nuance. To clarify, I don’t think you have to believe the U.S. is broadly superior to be patriotic — though I think the case could be made that it is better than other countries in fundamental ways. But rather I was arguing that the patriotic impulse to celebrate your country as being better than others is not a failure to recognize there’s “something arbitrary” about being American. Further, I think liberal Americans are just as susceptible to this particular patriotic impulse as conservatives.
To expand your metaphor a bit, I love my mother in two distinct ways. One, I love her because, well, she’s my mother and she gave life to me. That’s arbitrary; everyone has a mother. But I also love my mother because of the innumerable kindnesses and distinct things she did for me growing up. That’s not at all arbitrary — it’s unique to my mother. And in the latter sense, some mothers are objectively much better than others.
The same is true of patriotism. You can love your country because you were born here, and you can love your country because you rationally appreciate the Bill of Rights and its unique historical impact. The two views aren’t mutually exclusive.