Why is Obama letting Goldman Sachs off the hook and only fining them 550 mil?

If Bush was in office, they never would have been sued to begin with. Also it's a matter of practicality. They could spend years and millions of dollars fighting Goldman's legal armies in courts, maybe end up with nothing, maybe ending up with more than the 550, but no guarantee. Even if they did manage to get more, the Supreme Court would, I am sure, jump in to rescue Goldman and drastically reduce the award like they did in the Exon case.