Because the expenses that are killing us (housing, health care, education) aren't outsourced at all.
As far as I can tell (and according to most economists), the idea that "we can fix the middle class by going after China trade" is intuitive, simple, and wrong. And it's popular on both sides of the aisle. And historically, it's always been easier to find some group to blame than to fix structural economic issues.
So I think the further we go along this path, the less likely it is we will end up fixing our actual problems, and the more likely countries will be distracted by trade wars and maybe real wars in various parts of the world as those problems increase, and various groups are blamed instead of fixing economic policy.
This is separate from the human rights issues. But I think if we want to put penalties to try to address the human rights issues, we should be clear about that. Because if the penalty is for other political reasons it doesn't add an incentive to improve human rights, since that wouldn't make the penalty go away.
Why would we want this?
Because the alternative is a destruction of the USA manufacturing sector. Moving those jobs overseas only helps two groups:
1.) The Chinese 2.) The owners of capital in America, high up business men (the so described 1%).
The third group who may be helped, are everyday Americans who benefit from cheap goods.
What would imposing large tariffs do?
Goods are more expensive, so people can buy less. TVs, Clothes, Cars etc are more expensive. But middle class Americans keep middle class jobs. Right now the policies are ultra capitalist, the middle class is being gutted and replaced with a heroin epidemic.
Why dont we replace their jobs and retrain the workers?
The retraining of older workers for new industries has never been shown to work. Its an economic theory that has yet to play out in any economy on a large scale. I believe the root of Americas economic woes among the middle classes is this concept, which was conceived of and pushed hard in the 90s. Behind the scenes academics like Noam Chomsky fought hard against this concept, but the arguments never trickled down into the public.
In short, tariffs stop the outsourcing and middle class destruction. Things get more expensive, we accept that. If automation kills the jobs here, it still holds off the destruction of the middle class for another 15 - 30 years. Which is better than nothing.
I agree that retraining doesn't work. But I disagree that stopping trade can save the middle class. Manufacturing is only 7.9% of jobs [1] and stopping all trade will only slow the decline, with huge amounts of collateral damage for other jobs. Almost all jobs used to be in farming, but now they aren't. Manufacturing isn't going to be something that employs a huge number of people anymore. In China they're automating away jobs that pay $10,000 a year.
How are you going to help retail workers, 9.8% of jobs [1], as automation (Amazon warehouses) takes their jobs? Tariffs don't help them any although they'll pay for them.
There's real problems for the middle class and/or certain geographic regions, but stopping trade is a solution that almost no economists think will work. I'd rather try something more promising like UBI.
[1] https://www.bls.gov/emp/tables/employment-by-major-industry-...