To me, SBF embodied the worst stereotypes about the Effective Altruism movement. The not-so-subtle air of I'm-smarter-than-thou, the hubris to think whatever they have thought of haven't been thought and dismissed by others (probably for good reason), and a bull-headed focus on risk and return that can be exactly quantified, to the point of ignoring other, "softer" sides of the issue.
SBF isn't alone in this. In school, while interning for a competing hedge fund, I met a drove of Jane Street interns who thought exactly the same way, in terms of "EV" or expected value -- the mean outcome from a random event. For example, whenever we would go out for ice cream, they would try to flip a coin to see who pays, given the "expected cost" was same. This behavior is fine if you're a market maker betting 0.001% of your worth on a toss that you win 51% of the time, and I imagine this is why Jane Street tries to cultivate it. But unfortunately, in this hyperfocus on returns, they forgot that "risk"/"variance" exists, and sometimes flipping a coin will land you in such a deep hole that you can't continue to play the game long enough to dig yourself out of there.
You can read some thoughts by the man himself here, which flies in the face of all such work (Kelly bets, etc.) in variance minimization: https://nitter.net/SBF_FTX/status/1337250686870831107