I can say with a great deal of certainty that he hasn't read, or doesn't understand, any of the contemporary literature on market quality. If he did, he'd know that the efficient realization of market impact (you buy and the price goes up) is a property of effective markets. In the absence of actors to ensure this process of price discovery, all traders will pay unfair prices as small changes in supply and demand remain undigested.

I would also suggest that "young people at the best schools want to go skimming in the market" is reductio ad absurdum at best and ad hominem at worst, which sours my opinion of his ability to make a cogent argument without resorting to the Wall-Street-bogeyman trope. Then again, I suppose that's his job as a writer -- a story about the meek Canadian David battling the establishment equities market Goliath makes for a better read than a nuanced look at the role of various players in a complex ecosystem.

(Throwaway because my views are not necessarily those of my employer.)