The Americans never advocated free trade when they were a developing country. They protected their industries with heavy traffics from independence right up to after WWII - that's more than 150 years!
WTO has different rules for different types of countries. If you are a developing country, you can still join and less strict conditions will be placed on you. That's because everyone understands that what the Americans did for more than 150 years to protect their own industries when they were a developing country is necessary otherwise their domestic industries will be wiped out.
China is a developing country. She has only joined the WTO for say about 2 decades, not 150 years! China will open up her markets at her own pace and when she deems herself ready, unlike 150 years ago when gunboat diplomacy forced her to open up her markets to illegal and addictive drugs some of which were supplied by Americans including the ancestors of Franklin Delano Roosevelt. America only opened up her markets when she became an economic superpower after WWII.
