Contempt for America is so central to leftism that there would be no leftism without it.
Leftists have a Marxist understanding of history whether they know it or not. Hatred, not contempt, for the United States, as the strongest free market economy in history is axiomatic.
Ask a Leftist to 'smile' and you'll get a grumpy scowl ... ask a normal person to smile and you'll get a bright happy grin. Herein lies the difference ;)