So American companies, and thus their owners, will make more money. That sounds like capitalism at its finest.
Why would anyone object to that?
When government interferes with the free market by using tariffs, you end up with artificially higher prices which harms the average consumer. Capitalism is about managing your resources effectively to deliver a quality product at a competitive price. Tariffs and isolationist economic policies erode the efficiency of the market to the detriment of the individual consumer. That is not capitalism. That is government beauracracy pushing us towards another depression.