A pump and dump relies on manipulating others. In this scenario, the goal of the buying/selling patterns is not to manipulate the market into believing the price of the asset is something different, but just as a mechanism for transferring money between the funds.

It's also just a simple example of how it can be done. Many assets and derivatives are correlated to each other in the market in various ways. Their correlations can be exploited to allow you to do the same thing using an arbitrarily complicated set of assets instead of just one.

Some trades are required to be public, but the majority aren't. It wouldn't be too hard to hide the transfers in trades that don't need to be public.