I'm sure the ACLU will have something to say about it.
Misinterpretation of federal law can't be superseded by any lower court.
I'm sure their ruling will be overturned by a higher court like the SCOTUS.
IIRC, insurance companies tell you not to say anything to anyone after you're involved in a MVA. Except maybe to ask the other occupants if they're OK and then you shut your mouth about the accident.
Miranda rights mean what they say. He had the right to remain silent unless his attorney was present. Even if he had asked, the cops wouldn't have told him anything.