The United States is not a perfect government, and never has been or will be—or could be. But considering how the United States “could have” become a world-wide empire and did not, its restraint could be admired.
After all, we did not colonize the Philippines or Cuba after the Spanish-American War. (It might be fair to say that we just gave up the attempt in the Philippines after the bloody insurgency we faced there.) We’ve never made inroads into Africa that the major European powers did, and (despite some ill-considered talk from time to time) never made serious attempts to take over Canada or Mexico, both of whom have shared our “world’s longest undefended borders”, at least until recently.
Perhaps most importantly, even after being on the winning side in two brutal wars that ravaged Europe in the past century, we never did more than station more or less token – and defensive – military forces there, and have otherwise striven to assure those countries’ independence.