They should be able to show proof of this first then. In other words, it is concretely documented that certain cars are more prone to theft, therefore, the premium on them is going to be higher. The insurance company would be making a baseless assumption based on what for raising the premium for the Atheist plate?
Or what about this- if you don't like the insurance company's policies, you take your business elsewhere? Why don't we just let the company decide what it wants to do and how it wants to do it?
I have always found it ironic that the same federal government that the Bill of Rights was intended to restrict follows the Constitution less and less while it forces the Constituion on individuals and companies (both of whom were never intended to be covered).