Evil indeed, but this is the case with virtually any corporate chain. Someone posted about how H&M destroys unsold clothes rather than reappropriating them in some way, but this was not unique to H&M. Sweatshop labor should always be assumed as a default practice when shopping at mass market retailers. Even items claiming to be made in the US or Italy generally involve some form of sub-standard labor policies somewhere along the production process. This is not limited to clothing either, nor is it a question of price. A design house can make a luxurious garment in China for pennies and sell it in the US fit $600, resulting in more profit.
This is a matter of our own labor policies and given that we are at the extreme end of a capitalist society, there has thus far been no incentive to change. Any incentive would have to be financial. Under Pres Clinton, a bill was signed that resulted in fair labor practices in Cambodia, where they produced clothing for Gap & other US retail chains, but it was never renewed under the following congress.
The only way to avoid these seedy practices is to buy used clothing (and other goods) exclusively. Boycotts have never really worked. I don't claim to have a solution that works within the greater framework of our political system--to me, the entire system desperately needs a makeover.
