It is a show.
There isn't a way that congress can force AIG executives to give back or tax the bonuses, and AIG can get in legal trouble for NOT giving them (not honoring a contract). If they try anything,it will be overturned by the courts. You can't make a law, especially a retroactive law, against a specific person or company.
Bonuses unpopular with you and millions of others.
Politicians posture.
People have short memories.