Crypto at it's current price has a market cap around $2.6T. Obviously the liquidity is questionable, and since crypto isn't connected to any mention worthy real economic activity, a change in sentiment can quickly crash the price and liquidate leveraged positions.
While that's of course true for other assets also, crypto not being connected to production of real value, combined with the comparative lack of regulation, makes it much easier to manipulate.
In my view their interest, which aligns with that of all other major owners of crypto, is to acquire as much real currency as possible.
Acquiring more crypto by decreasing its valuation is not furthering that.
Maintaining a high valuation and positive sentiment in order to convert buyer's real currency into profit to cash out is what I believe their strategy is.
Presumably the hypothetical price change is reversible or there would be no point. So lower price, buy, raise price, sell, repeat. A dump-n-pump.