It's not a matter of having faith, I'm just familiar with the process. I'm not saying it didn't happen. I'm only familiar with CPS in New York, NJ, and PA and in the situation you described the state would never open a case based on what you described. Maybe they do in Tennessee. Are you sure it was just a caseworker who requested their supervisor open a case? Because if it's true that a case was opened against a family based on what you described it is definitely grounds for a lawsuit.
In my experience the biggest problem with CPS is actually failing to follow through with a case where there is severe ongoing abuse occurring. Too many children have died as a result of child abuse that was never followed through with.
I'm not sure how it's not victim friendly to say that CPS can't open a case without a thorough investigation. It's true where I live and I would imagine there are guidelines in every state. Otherwise they could just open an investigation any time they see a bruise on a child. Imo