You’ve never heard of this strategy before? If i tried to explain it, I would do a poor job, it’s happened a lot, enough that it is forbidden on most regulated exchanges.

In this case they buy slowly to avoid artificially propping up the price, then sell all at once to artificially drop the price, only momentarily. They don’t have to cause the entire price drop through selling everything they acquired, they just have to move the price down enough to trigger stop loss orders that they know about.

With this strategy they can accumulate assets while also taking profits on the shorts. It’s the retail investors who put in market orders or stop loss orders that get taken for a ride.

In their role as market maker they have all the information needed to minimize the risk of this strategy.