This idea of "IQ is meaningless, he's good at X doesn't mean is good at Y" is what dumb people tell themselves.

no surer sign that a defensive middlebrow poser is about to hold forth.

edit to add: I think most interesting systems are more complex than what a person can understand immediately.

He got into MIT where he excelled and then a job at Jane Street. Even really smart people get rejected from MIT and Jane Street. he may be a fool and delusional but he's not thick .

As for Jane Street, it is a hard place to get into, but MIT is one of the few places where there's an established interview pipeline, which definitely makes it possible for a non-genius to have some a chance of passing. Before Cracking the Coding Interview, it was much harder to learn how FAANG interviews worked ahead of time - same thing applies.

Saying that SBF is "average", if that means 100 IQ, is ludicrous, but SBF is merely very bright, not a genius.

A first semester law/finance student from a bottom tier university would know to shut your mouth and not document your crimes..

Running his mouth is his way of living in a reality where he still has a measure of control over things.

This is more on the spectrum of delusion and delusion has nothing to do with intelligence. Very intelligent people can be highly delusional.