I still think it's ideologically consistent with insulating companies from externalities. Without official investigations, companies can assert their own interpretations of events. Boeing did this with the NTSB recently:
In a hazard investigation you don’t want the investigators to have teeth. It’s not about finding wrongdoing it’s about determining what happened and how to avoid it in the future. If a company takes negligent actions referring to DOJ should be enough.
https://www.msn.com/en-us/news/us/boeing-punished-by-ntsb-fo...