* There's an obvious, legitimate want for the vehicle's head unit to ingest this data, in order to display a UI (or provide a voice UI) which allows the user to call a contact by name or read a recently received text message. Is this a poor implementation concept which has mostly been supplanted by better implementations (Android Auto / CarPlay), sure, absolutely but it's not some thing that was added for the express purpose of "stealing" information. It's a long-standing set of features which use obvious, standardized Bluetooth technologies to fill an obvious, straightforward user need. Nothing weird there.
* There's no sign whatsoever that there was any collusion with law enforcement in the construction of these systems. They're just badly implemented, vulnerable software which is exploited by a forensics vendor (just like literally every other piece of hardware and software under the sun).