The courts have long since determined that the police have no responsibility to protect anyone that they don’t have a special relationship with - they are only required to take reports of crime and investigate such reports after the fact. They are not even legally required to attempt to apprehend the responsible party.
Legally, the officer did nothing wrong. Morally and ethically is another story.
You do acknowledge that the courts often get it wrong, yes? Or is this ‘settled law’ to you?
A public servant, paid for by public tax collections, has duty to those whom he serves. It’s like the military. It’s not a meal ticket. It’s service in exchange for opportunity and modest compensation. There is risk of bodily harm and even death. This is why we honor our heroes. There is no honor for cowards.
The courts have been used to destroy many great institutions. This is another.