Apparently, Mt. Gox doesn't like to sell at lows and only on highs 
he never sold those bitcoins on any exchanges and when you buy/sell anywhere apart from exchanges you do NOT affect the market. so who cares whether he sells on "lows or highs".
you can read the full story here: https://news.bitcoin.com/the-mt-gox-whale-explains-his-crypto-selling-strategy/
Quote
According to the trustee, he consulted “cryptocurrency experts” during the BCH and BTC sales, and he did not use the traditional method of using a digital asset exchange.
as i have always said this from the day this news hit the media, this was 100% FUD to cause panic and manipulate the price. now this latest news simply marks the end of that FUD.