And besides, the majority (if not all, given Volcker restrictions) of sales and trading is from market making, rather than risk taking / directional punts on the markets.
I'm not trying to pick on Goldman. They were just an example of a large institution that makes huge amounts of money by doing exactly what these guys did. Betting against the market is absolutely routine behavior.
As for Goldman, do you really think they are clearing 100 million a day by being market neutral and just collecting premiums? When they buy/sell it absolutely moves the markets just on the sheer volume.
“Do you know how naive you sound, Michael? Presidents and senators don't have men killed.”
“Oh. Who's being naive, Kay?”