If this was done before Mt Gox happened, then irregularities would have been detected in advance and we might not have had the Mt Gox incident. The regulated exchanges must function as "safe" area for people to trade bitcoins and if they fail in doing this, we will suffer the same fate as we did with the aftermath of Mt Gox. The government have a duty to protect the consumer from questionable practices or services.
The Chinese authoritarian communists need to control people to keep their power and wealth. To control people, they control the capital and speech.
Hence they fear bitcoin because it isn't subject to their control (except it too many miners are concentrated there).