You got a opinion, unless there are court cases to back it up, it is just a opinion. And that opinion goes against what the attorney general has on their website. There is no law against open carrying in a vehicle, if the gun is not hidden from common view, in this state it is not concealed. I have been stopped for license checks in a commercial vehicle and not one DOT officer has said anything about my gun. And they work for the state.
In the long run you have to decide for yourself. Some people put the gun on the dash, I don't. When in the car I put the gun belt around the passenger seat for comfort, it does make it more visible. I am not to concerned about needing a firearm while driving especially on the freeways. There are just better options than using a firearm while driving.