Can you explain the logic (or lackthereof) behind the "My country, love it or leave it" argument?

My country, love it or leave it.

This is the notion that this country (whichever country that happens to be) has it’s own set of laws, traditions, and customs. If you disagree with or speak outwardly against these laws, traditions, and customs, then it is irrational for you to remain in this country; it would be better of everyone involved if you were to just leave and find a country that better suits your beliefs.

This argument is usually used against progressive discussion which calls into question the legitimacy of the established laws and traditions. “My country, love it or leave it” is in direct contention with the philosophy that laws and traditions should be changed for the better, rather than simply acknowledged and obeyed.

In modern settings, the argument has been used against those opposing the Iraq war, questioning the role of private enterprise in areas such as health care, education, etc, arguing against the unchecked dominance of Christianity, supporting homosexual rights, and opposing the USA Patriot Act, to name a few.

What are your thoughts? Is this a valid argument? If so, what is your rationale? If not, why do you feel that it is not satisfactory? Why do you believe that it is relatively popular amongst citizens in the United States? I am interested in your responses. Thank you.