I wouldn't go that far. They're a small part of the total market - most of the trading takes place in the west. I think people would like China to continue to participate in the great bitcoin experiment, they have stars in their eyes about 1 billion people etc. The reality is most chinese don't participate and they are behind a firewall anyway.
The rise up to $4800 was driven by the west. It went too fast, we'll see a correction on the back of this "news", and then it will resume it's upward movement in a few months.
https://bitcoinwisdom.com/ says to me they have more than 50% the volume, not so small
Coinmarketcap says otherwise:
https://coinmarketcap.com/exchanges/volume/24-hour/Looking at exchanges with fees
#1 is Bitfinex, which is Hong Kong based and exempt from the China rules (as it is subject to HongKong Sar rules)
#2 is Bithumb which is Korean
#3 is Bittrex which is American
#4 is Poloniex which is American
#5 is OKCoin - this one IS Chinese
#6 is GDAX which is American
#7 is Kraken which is American
#8 is Huobi which is Chinese
#9 is Coinone which is Korean
#10 is Bitstamp which is European
#11 is Gemini which is American
#12 is HitBTC which is European
#13 is CHBTC which is Chinese
#14 is Korbit which is Korean
#15 is BTCC which is Chinese
So the Chinese exchanges are lower down the list and definitely total way less than 50% of trading.