I agree with some of your points, but there isn't much individuals can do in some cases. Many people can't afford expensive goods made in the domestic market (much like many people cannot afford healthy organic food). In some cases you find that all the products available are made in sweatshops.

The onus must be on the manufacturers.

When you shift factories out of your country, the pollution there decreases, but it increases somewhere else.

Besides, while I hope China is addressing its environmental issues, it is still a dictatorship which disallows open discussion of many such things. It not only has sweatshops but concentration camp labour, and disallows proper trade unions.