The only point in my opinion would be to try and create panic so he can buy them all back for less later.
Imagine that you sell goods for bitcoins in a dollar-exchange rate linked way, and you have a sizable amount of bitcoins available. You have an income stream in bitcoins already, but if you let the price be too volatile you run the risk of having people wait to purchase for spikes in the market, so the majority of your income would start off with a slight exchange rate loss. If you have a projected growth curve for bitcoin, you'd be incentivized to sell whenever it grew too fast to try to mitigate your exchange rate risk.
I don't think this is what is happening, but its an example of an incentive that could cause this type of behavior.
-bgc
It would make more sense to sell down to $13.50, and then place asks for all of your coins as $13.55, $13.60, #13.65, etc, and if/when the price starts to drop
then sell the rest as a market order. But then again like its said before, someone else could dump $100k coins and you would be out of money. So businesses needing to sell is a valid point.