What's even supposed to be the logic here? Where do you think that "$250M" figure comes? Why are you assigning some special meaning to it? It's pulled out of the ass of the very same judge who granted SBF bail.
Here's a longer explanation by a former federal prosecutor, current criminal defence attorney https://www.serioustrouble.show/p/how-did-sam-bankman-fried-...
Bail bondsmen basically do not exist in federal courts.
But sure, regular crooks generally don't end up in federal courts. I think that's probably where this confusion stems from.
The only "news" source I found discussing this was also speculating, and was a right-wing political blog. Not a source I'm comfortable relying on (even if it had been a left-wing or centrist political blog). But I didn't look very hard; open to being corrected if someone has a good source on this.