USC pertains to FedGov activities. Whatever Congress votes through and gets signed gets paraphrased so nobody can possibly understand it and then is printed in the USC. Could be anything in there and none of it matters unless someone is working for or dealing with FedGov.
Um, how shall I put this? Wrong.
The USC is the United States Code. It is the body of Federal Law, usually referenced as the USCA, or United States Code, Annotated, which is the standard legal reference and includes footnotes on the current judicial interpretations of each provision. The states follow a similar model -- for example the laws of Georgia are compiled in SCOGA -- the State Code of Georgia, Annotated.
The USC is enforced by the FBI, BATFE, USCG, ICE, TSA, EPA, OSHA, IRS, and the rest of the fed alphabet soup, whether you choose to work for or do business with the federal government or not.