You act as if it's the countries that are doing the trading; it's not. It is the businesses and other entities within the countries that are doing it. They are doing it because it benefits them. If a company is doing overseas manufacturing it is because they benefit and it isn't the United States that made that decision.
Merriam-Webster: "The meaning of TARIFF is a schedule of duties imposed by a government on imported or in some countries exported goods."
Apparently the dictionary is "woke."
Wikipedia: "A tariff, or import tax, is a duty imposed by a national government, customs territory, or supranational union on imports of goods and is paid by the importer."
Oxford Economics: "Tariffs are taxes imposed by a government on goods and services imported from other countries."
(disclaimer: I'm a CEO of HTMX)