Free trade unfortunately also leads to what is called a "branch plant economy" where policy decisions are made by foreigners with much less interest in your national or regional success.
Trade makes everyone better off, in general, but is risky, because policies can change. Free trade in particular gets even riskier as it means the populace has fewer levers of influence against the corporations. Canada is experiencing this with auto manufacturers - many Japanese and American (some German) companies build cars in Canada and Mexico for the broader North American market because of North American free trade and lower labour costs in both countries (the exchange rate, single payer health care in Canada, more reasonable unions, etc). But now so many jobs depend on these companies, the Regional Governments can't let them leave in economic downturns. So they subsidize. Is this all a net positive? Probably, but it's hard to know.
When you accept the upside of trade you need to accept the downsides - but most don't. "Let the free market choose" isn't an answer because we live in a Democracy, one feature of which is to prevent the market from getting what it wants when the people don't like it.
The USA dominates technology with only a few counter-examples in Europe (SAP, Amadeus, ASOS) - but LOTS in China. If the future is going to be these companies diversifying into every other market ("software is eating the world") you can bet there's justifiable anger at the U.S. (At beating them in a new area of knowledge and practice) and a desire to put up barriers while they get their shit together as China did.
This isn't war, it's competition. There's a big difference.