People don't know their own laws because there's hundreds of laws each year that go on the books across a country and in the states. Do you know all the laws pertaining to driving, working, shopping, walking, drinking, fighting, defending, etc for your community?
I work in a law firm and I'm learning daily new things about real estate (commercial), transactional law, SEC laws, environmental laws, EIRs, and I also am a big fan of guns in California so that presents gobs of other laws that nobody knows...and I haven't even scratched the surface of the applicable laws that I fall within and without daily. Cops don't even know the laws and they are supposed to know them..they even carry around a huge penal code book with them and oldtimers are scouring them once in a while.
anyway..that's the long answer. Short answer = there's lots of laws.