Right, my understanding is that the US along with most developed countries provide agricultural subsidies and/or tariff agricultural products from other countries or provide other formal or informal trade barriers. Makes sense, in a way, as you need to keep your agricultural base if you have one. It seems logical that this could extend to other industries, car manufacturing, weapons/missiles, semiconductors, other various technologies. Healthcare. You get the picture.
But I think your comment about Trump is not quite nuanced enough and of course you have to include that the US is negotiating with other powerful parties like the EU and China so it's not really always the US negotiating with weaker parties. At the negotiating table I view each of those big 3 has having many cards to play, and both weaknesses and strengths that can be exploited.
When I say it's not nuanced enough what I mean is that, for example, American technology companies are simply banned from operating in China. In Europe, until I believe July or something American car exports were tariffed at a 10% rate, and then you have policies like the Online Streaming Act in Canada (I'm not exactly up to date on the current status but just recall it existing).
So while Trump's negotiating style is, arguably something to abhor, I think painting these engagements as simply a matter of Donald Trump isn't interested in free trade or sustainable relationships to be a bit off the mark. For example, you can't simultaneously claim that Donald Trump isn't interested in free trade while ignoring trade barriers put in place before he was even elected president. I'd also argue that in general most countries and people aren't actually interested in free trade and that it's more of a political tool, because that would require abandoning subsidies and protections and there are obviously very bad potential repercussions of doing so.