There are literally thousands upon thousands of reasons in the Federal Code for the police to arrest you. That's the very essence of a police state. Everything is literally a crime. As Lao Tsu said in the 6th century, BC: "The more artificial taboos and restrictions there are in the world, the more the people are impoverished...The more that laws and regulations are given prominence, the more thieves and robbers there will be..."
In an environment like this, police cannot merely be keepers of the peace. They must be enforcers of the law. And enforcers use force, of course—intimidation and sudden and shocking violence in order to make you obey. And compliance is exactly what the police expect. They long ago stopped being “public servants” and became more akin to plantation overseers.