They are the same as us that wants to earn profit from it. They bought 450,000 btc but within those 9 months, nothing really happened. You might think that they are manipulating the price, they can but they can't do it properly. Bitcoin is a decentralized crypto currency, there might be an effect on what are the whales are doing but I don't think we should worry about that now.
People FUD would spread around and the market would fall big time again but the question is what would happen next after they do it?
Would they come back again or would they just leave crypto for good ?
We couldn't know what would they do on that huge amount even if OP's information isn't accurate we all know that a whale could really do it.