If criminal cases are a red herring, then why do we even need laws or police at all?

It's eminently possible for anyone to go around tasing anyone else. Law enforcement fundamentally relies on post-facto punishment. Most people don't tase pregnant women due to a sense of common decency, but most of the remaining don't do so because of the threat of punishment. When you remove the threat of punishment, it allows the deviant group to act out their desires with literal impunity.