I don't see much evidence of Trumpism here.

The US has a long history of believing that no one can be more efficient than a US company so under pricing is proof of dumping.  In conjunction with this US subsidies are always fair and justified, or not even a subsidy, but any foreign subsidy is unfair.

This attitude is why it is important that NAFTA retains Chapter 19 dispute resolution.  Without it trade rules would be US trade rules which almost invariably favour US companies.