Free trade is utopian because it runs counter to the way humans have always behaved.
When humans develop markets, they impose all kinds of restrictions on those markets. U.S. history provides an excellent example of typical market restrictions and interventions. Starting in the 18th century the federal government subsidized the construction of roads and later railroads. Like every other country on Earth, the U.S. has always restricted and shaped market activity to promote its own particular societal goals. Now supposedly things are going to change.