If you hold tons of something that if you sell them all at the same time the price will drop the standard thing to do is to sell them over a period of time so you get the best price you can. The way Binance did it, they knew they wouldn't get the best price.
A good example of this is Tesla stocks and how Musk is selling them. He's not just dumping out all he wants to at this super high price he is slowly doing it. And it's still affecting share prices.
