This comes from a common mindset that people in prison deserve no rights because they broke the law. They don't take into account the fact that there are people

This comes from a common mindset that people in prison deserve no rights because they broke the law. They don't take into account the fact that there are people there who don't deserve to be (either because they are innocent, or because the law they violated was unjust), and if incarcerated people have "no rights", then they can't fight for their freedom.