China is notoriously rife with corruption. WTO entry will simply export that corruption into the international marketplace. The country will be able to set its own very poor president of non-compliance to WTO regulations, and export further corruption into the WTO itself. Even more Chinese workers will be laid off, and even more peasants will flood into the cities. The people of China know that their country's economy is already quite precarious.
Many areas stand on the brink of collapse.
Nearly everyone in China should be able to foresee this outcome. It's incredibly simple. Even those in power cannot deny it, and yet they do.