Technical point here but opinions are not illegal to have.
Besides that your point is missing the fact that you are dealing with outside services that provide a contract for their usage (GPS, GSM). You should be free to program your own devices but if you use an external service, then yes they can specify how you use their service. Those are contractual obligations. Cars on the road have clear safety risks and those are legal obligations. None of those obligations should govern what you do with your device until your device interacts with other people and/or services.
Besides that your point is missing the fact that you are dealing with outside services that provide a contract for their usage (GPS, GSM). You should be free to program your own devices but if you use an external service, then yes they can specify how you use their service. Those are contractual obligations. Cars on the road have clear safety risks and those are legal obligations. None of those obligations should govern what you do with your device until your device interacts with other people and/or services.