It is true that there has been some contraction in employment in labour intensive industries such as textiles and footwear in rich countries over the past 20 years as production has moved to countries in which labour is cheaper. However this is part of the process of development. It would be condemning less developed countries to even greater poverty to ban restrict their ability to compete in industries like textiles in rich markets. The campaigns by the unions are allied to those of textile manufacturers in rich countries. They are less concerned with supporting worker rights in poor countries than they are with protecting declining industries in rich ones.
Wage levels differ between countries according to the levels of education and productivity.
The experience in countries like Korea is that as countries develop, their wage levels rise and the focus of their industry shifts from labour intensive to more capital and knowledge intensive industries. The clearest response to the union arguments about trade and wage inequality is contained in the OECD document, Open Markets Matter.