The alternative to allowing manufacturing to move to China is higher prices for goods in the United States. Instead of having really cheap TVs, TVs are more expensive -- they are manufactured here.
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.