States have window tinting laws to help police to pull over, harass, identify, and/or profile people in the pursuit of profit and control. The main justification for window tint laws is "protecting law enforcement", which is itself is a bad excuse, but everything beyond that is definitely complete bullcrap because the tinting laws differ so completely between states, with some states not caring at all. Many states with tinting laws have zero laws about maintenance or inspection of vehicles which is all but proof that the safety of the public is not even a real consideration. You can literally have sharp jagged chunks of rusty metal hanging off your car and its not illegal.