their users lost their Bitcoin due to hacked exchanges, and now they are all asking for a refund. Why the hell Mt. Gox should sell that tremendous amount of Bitcoin to refund their users. They should refund in Bitcoin, so they didn't need to liquidate it.
This is not up to the trustee, but rather the majority of the creditors and what their needs are. They made the decision to give them a monetary reward, equal to their share of the money that was recovered. <more or less $400 per bitcoin>
Keep in mind that many of these creditors are probably not involved with Bitcoin anymore and most of them will sell the coins as soon as they get them. If all of them do this at once, the price will go down hard. <166 000 coins dumped on the market will crash the price>
I would prefer a slow controlled sell, over a much longer period to protect the price.