tariffs are “central planning”. Why would they put a higher tariff on greige stock than on finished goods? Because it’s complex, and they screw up. But somehow free markets manage to do things well, because screw-ups go away. When the central planners do these things, the mistakes just roll and roll.
The idea of "free markets" in international trade is nothing more than a subject for theoretical exercises in classrooms and coffeehouses. The U.S. doesn't even have "free markets" when it comes to its own domestic economy -- let alone with our trading partners.