It's not a bluff. From what I've read, fighting CPS is expensive. (Though I would raise the issue with the police chief.)
I'm reminded of how Georgia will pay foster parents of homeless kids more than it'd cost to simply put a roof over those kids' families heads. https://www.propublica.org/article/georgia-housing-assistanc...
I don't ever leave my kids (one that is under 6 and one that is well over 6, but not yet 13) alone in a car, since I don't want police or nosy passersby injecting themselves in a perfectly benign situation.
I also disagree with framing all police as “murder junkies”.
Antagonizing a local police officer is a terrible idea unless you are wealthy and/or well-connected. Most are kind, but not all are, and antagonizing the wrong one can make your life hell.
(I also agree that the vast majority of police are not "murder junkies". But it's also not surprising that a handful of folks like that do join an organization that nearly always manages to protect their members from repercussions when they use lethal force.)