Well I believe Roger and Craig are fuckwits, so they could of contributed, but that was a big bubble so no doubt the bear market had a lot of contributors. Why do you rule the Chinese out as buyers though? I am not saying they are solely responsible and I know that the Chinese control the market is pure bullshit. But, that doesn't mean they can't contribute to these things.
The Chinese obviously have a lot of money and if you look at the worlds housing markets you can see that they are very keen to get their money out of China. Despite the capital controls they are still able to do this with ease I might add. So, why wouldn't they be trying to escape a devaluing currency? that's what I'm doing with Bitcoin.
The 2013 bubble run ups happened almost exclusively due to the Chinese exchanges driving it, they had a super small market to work with, thin float (low liquidity), and massive amounts of leverage (X1000) going on at the time. That's why the volatility was so high. The massive leverage was the key, and a lot of that leverage was likely naked long/short. All fingers point to the Chinese exchange owners themselves and their super rich whale trader friends running the game. Who else could back that shit but the insider traders themselves?
Of course they had to have accounts on Mt. Gox and some other exchanges as well to help control things. But it's clear the game was largely over for the Chinese when the PBoC first shut down leverage, demanded transparent accounts and reporting, and then shut down the exchanges.
That kind of out of control volatility wouldn't happen the same today (without Bitcoin derivatives that is) because the Bitcoin market is so big now, so many exchanges now so the loss of control, and that kind of massive leverage just not available anymore.