Yeah I don't really see law or medicine as any different in this regard.
People all have a basic idea of what makes you ill, what various diseases, treatments etc. are. But most people don't understand the intricacies of the endocrine system.
People all have a basic understanding of the law, what kind of sentences to expect for what crimes, how court works etc. But most people don't understand <INSERT_COMPLICATED_ASPECT_OF_LAW>.
You see where I am going with this..
People all have a basic idea of how the internet works (you connect to the network and data is returned to your computer), the difference between 4G and Wi-fi etc. But most people won't be able to explain the difference between RSA cryptogrpahy and eliptic curve cryptography.