American law is not Jewish law, and it is more similar to the laws of the people of Sodom, who would band together to steal, each in the amount less than actionable in court. Although what they did was not nice, each one could not be sued.
However, American law is not the law of Sodom either, and technically people can be liable for downloading music. What remains in question is this. According to RIAA, this is the law and it should be enforced. The other side claims that RIAA, its clients, and their lobbying groups influenced the law to be written the way it is. Then the argument is precisely the fairness of the law and if it should be changed to fit the new times.