It supports the WTO because the WTO limits the tariffs that can be placed on its exports down to what western countries impose on each other, whilst at the same time allowing it to run high tariffs, because it applies those tariffs to everyone. It also allows it to fund its state-owned companies as much as it wants, giving them an unfair advantage against private companies that can't be funded by the government, due to subsidisation rules. The WTO also places no minimum workers rights stipulations on China. Nor does it penalise copyright infringement. Basically, the WTO works between western countries who play by the same rules, but China don't play by those rules, so the west sees fit to restrict WTO to itself.
Good to see you standing up for China once again, Arseling E. coli connoisseur.