It isn't. Read the quoted section from Russel Clark, the BIS has been talking about this (they specifically mention levered hedge fund positions), and they specifically mention an arb between cash bond and derivatives (do you know the history of this trade? It blew up twice in the 90s)/point out that some funds are running with a lot of leverage (is this repo? I don't know, but it is likely given that this has always been a financing source and the BIS are saying that it is).

So not nonexistent. The quotes look completely fine (I have looked at clearinghouses quite a bit, Russel Clark understands them...obv, the guy is not an idiot).