1. I think China want to temporarily crash the market so they can collect more BTC (and other coins dirt cheap) before announcing that they are officially adopting. At that point BTC (and other crypto) will sky rocket.
2. They don't want their citizens to trade cryptocurrency and earn (relatively easily) in fear of losing their cheap labor force. They will then try to make it as difficult as possible for it to flourish in their country.
Which is it???
They seem to crash the market to buy back in, im not sure how much they can make in such a small market when its spread out between so many people. I should imagine its mostly the top bitcoin players who control this thing and pay off whoever needs paying off. On the bright note if they big players want to do this in this market its bullish long term. Things ive noticed is the bad news comes in installments, like they are checking if its the right time or something.