Sure, one firm able to absorb an entire market, one that is worth trillions of dollars. Pluh-eese.
It's not the "whole market", it's the S&P e-mini's and with the volume and alleged self selling it's entirely possible because the index is watched by others to infer movement. Leverage is the key.
Personally, I think the naked shorting scandal is going to eclipse this, this guy will get buried eventually and lose his ass.
You are better informed than I about the markets involved. Still, I am very dubious that one firm can truly control the market, and artificial pricing creates opportunities for others.