While there is ongoing debate as to its significance, the message was arguably a commentary on Satoshi's less than favorable regard for the parasitic, unstable and inflationary nature of the contemporary banking system, as well as a statement on Bitcoin being able to provide a more equitable transfer system by cutting financial institutions out of the equation.
Elsewhere, Satoshi had elaborated on banks, again is a less than flattering way:
"Banks must be trusted to hold our money and transfer it electronically, but they lend it out in waves of credit bubbles with barely a fraction in reserve. We have to trust them with our privacy, trust them not to let identity thieves drain our accounts. Their massive overhead costs make micropayments impossible."