Jenelle doesn't take care of Jace because she does not have to take care of Jace. She's got somebody to do it for her and allows her to be irresponsible. I've said before that Jenelle was raised to act irresponsibly, and not held to standards. Yelling, and not requiring, is not any way to raise a child to be a responsible adult. I do believe that Jenelle does have it in her to be responsible for Jace, but why bother if you don't have to, and all you are going to do is get yelled at....well, anyway, I could see that being her train of thought. All she seems to want to do is to get away from her mother's negativity. Convoluted thinking, but logical to some.
And the police officers are out there to do their jobs, and that is what they were doing. They are qualified to know about the differences between criminal or civil happenings....or, at least, we hope they are. It comes down to the difference between what IS their job and what is NOT their job.