How do we stop them and fuck them up? easy, don't panic sell when they release more PBOC messages. If they see that they can't manipulate the price with those PBOC messages,, they will try to stop shorting and they will start longing pushing the price up.
Investors and traders care for the profit so even they know what the is latest trend and the effect of it to the current price decrease, they are securing the profits rather than to hold it for long. They can back again anytime once the price went to decrease again so no worries for them if they will take out for now and entered later.
Only those long term bitcoin holders will not be dragged by this even the price went down much more. That's the spirit in their optimitism about the big price increase that will in bitcoin someday.
i wouldn't call it optimism, it is -in most cases- a good study of bitcoin and its future and then investing as long term strategy. and i have to say in the past 8 years this strategy was successful since the price has been rising ever since and the pumps like mtgox or the halving pumps were a good chance for others to get in and those who were in to make some profit and buy again.