Some leftwing Americans refuse to celebrate Independence Day because they think America stands for oppression. Some Americans on the religious right refuse to celebrate Independence Day because they think America stands for abortion, SSM, &c. Ironically, these are mirror images of each other.
Although I often defend my country against knee-jerk anti-American sentiment, I've never been much of a flag-waver. That just isn't my thing.
However, I'd like to point out that to say America is too evil to celebrate, or the flag is a symbol of oppression, or whatever, is terribly simplistic.
"America" is an abstraction. What is America? American is many things.
i) America is the land. Consider the national parks as a sample.
ii) America is a history. There's pre-Colonial America. There's Colonial America. The America of William Bradford, Cotton Mather, and Jonathan Edwards.
There's the westward expansion. There's the history of your grandparents. And your parents. There's the period you were born into. Or when you came of age. The 20s, 40s, 50s, 60s.
iii) America is a patchwork of distinctive regions, viz. New England, the Mid-Atlantic, the Midwest, the upper South, the Deep South, the Gulf Coast, the Mountain States, the Pacific. These combine distinct geographies with distinct histories.
iv) There's a patchwork of ethnicities.
v) There's a patchwork of religions.
vi) There's American culture, viz. architecture, music, sports, classic cars.
vii) There's famous American cities, viz. New York, New Orleans, San Francisco, Las Vegas, Chicago, Boston, Charleston, Seattle, San Diego, Savanna, Saint Augustine, Nashville, Albuquerque, Flagstaff, Philadelphia, Little Havana, &c.
viii) There's small-town America, where everyone knows everyone else.
ix) There's the idea (or ideal) of America. That can be a religious idea ("a city on a hill"). That can be a political idea (The Declaration of Independence, the Bill of Rights).
x) There's the American mythos. The idea of America in novels, viz., The Last of the Mohicans, The Scarlett Letter, The Red Badge of Courage, The Adventures of Tom Sawyer and Huck Finn, The Great Gatsby, Invisible Man, The Martian Chronicles, The Moviegoer.
There's the idea of American in movies, viz. the Western, film noire.
To the degree that Americans act on the mythos, that can become a reality. There's a circular dynamic.
I'm not making a statement for or against patriotism. I'm just pointing out that "America" stands for so many different things. Different things to different people. You can't really generalize.