The elites choose that trade policy because it is efficient (specialisation), and because the prevailing wisdom since WW2 is if you trade with someone you don't war with them, so US heavily encouraged global trade.
Idealist nonsense, offshoring of manufacturing capacity from highly developed countries with large union penetration to countries with lower labor costs and more lax worker protections has literally nothing to do with comparative advantage and everything to do with enabling ever more brutal exploitation of labor and higher profit margins