“Don’t the states have to recognize the acts of other states? If your home state was willing to register your car the way it is, can they ban it?”
Ask the dudes in Montana bringing back dope from Colorado ...
What does that have to do with what's legal for a motor vehicle in one state versus another?
This is like an officer in Idaho pulling someone over driving a car from New Mexico. In Idaho, two license plates are required, by law, one on the front of the vehicle, one on the back. New Mexico only requires one (on the back) and only issues one.