You think now China using low price to sell their merchandise , and made American people unmployment ?

Although manufacturing sector may have shrunk in the US due to global competition; the effects of lower prices made several goods more affordable to the average person. Your argument of unemployment is only applicable to those whose jobs are lost as a direct result of this.

The unemployment situation in America is caused by the economic collapse > caused credit squeeze > caused by the housing bubble > caused by availability of sub-prime mortgage to the average man and surge in demand for housing finance & supply backed by money market funds.

It is not only one factor,but it is unfair. China has also using trade wall including tariff and non tariffs barrier against American products.