Because bail numbers are fake. He put up a house and some other money but nowhere near $250M.
If he doesn't have/can't borrow the full bail amount, I see no reason for him to be out on bail. Normal people don't get this kind of privilege.
A bank is private business they can choose how to go about their risk and reject anyone for any reason the criminal justice system needs to be fair to all the participants in it .
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[1] yes , there are plenty of people in jail only because they are unable to post bail or some other fees but that is not the same debtors prison