Compared to the alternatives, Jane Street doesn't exactly select for street smarts. (Nor does MIT, to be frank.)
Sam Bankman-Fried's statement to Tyler Cowen that he will take any positive-EV bet regardless of the standard deviation of returns, sounds more like a learned-by-rote answer to an on-campus trading interview question rather than a core tenet of a trading philosophy. Professional traders at major institutions (including Jane Street) care about things like Sharpe ratio, value at risk, and position sizing. Not to mention that Jane Street asks Fermi questions in their interviews. I wouldn't be surprised if the average MIT senior with three or more trading offers could proffer the same kind of demonstrations/responses as what you describe.
He must be on some weird drugs that just has him spewing his points left and right. What people are misinterpreting is his claim that he was careless and that the accounts where poorly labeled. Those aren’t him trying to say he wasn’t a fraud,m, that’s him saying that he could have kept the fraud going if only they hadn’t been too highly leveraged.