Conviction for robbing a CS gets you up to 25 years in average State Pen, hard time.
Conviction for robbing a bank gets one 20 years average in a FEDERAL pen...easy time.
Why do CS's get robbed a thousand times more than a bank does??
Because they know that the State courts are swamped and the States' resources are finite (they can't just print money and deficit spend on a continuing resoloution like the Feds) and they can likely plea down to a slap on the wrist for the CS job.
The Feds are not so forgiving when you monkey with their FDIC protected institutions. They can't let that happen, or the confidence in the Federal Reserve System, which is all the currency is based upon these days, would evaporate. It's always about control...... and they will do whatever is necessary to keep their system going.