There are 200 odd countries in the world, but you belive your country is the best, well, because some number from over there want to come here.
You want to belive your country is the best, your whole life you've been told by your authorities that it is the best, that everyone wants to come live here, and you've heard this as so often you've come to believe it.
This is fine - you are not alone, most people in most countries are perfectly happy with their system. Most people don't want to immigrate - whatever they have, wherever they are, is the home they know.
Unfortunately believing we are the best prevents us from being better. We cannot fix it unless we admit it is broken (whatever It is) and if we start from a position of "we are the best" then it's hard to admit some stuff is broken.
Why, instead, don’t these million plus seek a life in China or Cuba, if that system is, apparently better than the North American system?
In addition, Americans are actually free to leave but very few do, especially those affected by your examples of suffering from the system. We know people of very few means can emigrate, so given poor Americans have more purchasing power than poor who move here from elsewhere, if it were repressive we’d see an exodus of Americans to greener freer pastures.