The shutdown wont be for long. The real reason is because the chinese are changing their remimbi to bitcoin and investing in opportunities overseas and the govt sees this as an outflow of resources. The country wants to focus on domestic development rather than use its wealth on development on foreign soil. So shutting down existing exchange facilities is the fastest and most effective means of control.
RE: Breaking: China To Shutter All Bitcoin Exchanges - An Interview with Simon Dixon of Bank To The Future