Many Americans feel cheated, whereby they give better terms to other parties and don’t even get respect in return. So they now support a movement to mirror that behavior.
This is an example of the iterated prisoner’s dilemma: one side defected on a partnership for their benefit, trust collapsed, and now the originally cooperative partner is acting selfishly as well. Reciprocation is a fundamental part of relationships.
The US isn’t the entity that needs to hear “cooperating is better than a zero sum mindset”.
Edit to respond:
Most of those people are upset about that as well:
- foreign owned farmland and corporations;
- foreign owned condos, etc;
- inflated stock prices enriching Wall St relative to Main St;
…and so on. What you’re describing is the concerns of the petite bourgeoisie who have benefitted from inflated stock prices, housing prices, and land prices.
For Trump supporters, ending that distortion in the market while boosting domestic labor is a win-win.