'Free' trade benefits industrialized nations, while mercantilism benefits developing nations. Every currently industrialized nation has, at some point in its past, been incredible protectionist, blatantly violated IP laws, had atrocious safety, employment, and pollution regulations, and large taxes on foreign imports.
China is just catching up to what the rest of the developed world has gone through.
Are you expecting them to look at the history of how the United States, and Europe developed, and go: "Well, gee, protectionism, lax safety regulations, and access to foreign resource markets worked really well for all these other countries... But we shouldn't repeat their success!"