Where are “people” (Conservatives) getting this idea from? Governments do not have total information of the production of all goods produced in the world. How hard is it to understand they just look at the shipping location of items and their classified category?
Well this clearly won’t do any good, but Richard Wolff has a lot of good explanations on tariffs on his youtube channel.
I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy: