I am not 100% sure that he is a crook per se, or a scammer (which is the word being used a lot around here).
From what I have read (and in fairness, just following casually), it seems to me like there is at least some possibility he just had zero idea of what he was doing from a business standpoint. Both in terms of what is legal/allowable, and how to be prudent in running a business. But had about 1000x more hubris that was good for him.
- He just kept buying companies in trouble, and assumed the money tree would fund it all, and he would make it work because he was so smart.
- When his one company needed billions, he took it from different company and moved it - acting like they were all 100% his and there were no rules on doing that, or other claims on the money. Or that he could break the rules, and just put the money back once the money tree took care of it, and by the time the dust he would just pay a fine.
- There was no one else involved available to say "hey you can't do that" like, idk, a seasoned CFO or a Board Member to hit the brakes and prevent that kind of egregious violation. Just everyone in charge way too enamored of their own intelligence and infallibility.
So it's possible
that it wasn't a scam with malice aforethought.
But all that said, it definitely could be that he knew exactly what was doing and was trying to sneak out as much silverware as possible before the house burned down. If there's some smoking gun stuff out there let me know, I haven't been following that close.
Note- I am talking about SBF particularly, not crypto in general, of which I am very skeptical.