Personally, I don't think the parent's are necessarily "abusive," but if they refuse to deal with the problem, I do not see how anyone can say it isn't medical neglect - thus completely right to have DCF get involved.
To compare failure to meet a child's medical needs with driving them in a car is a silly stretch of the imagination. Maybe to refusing to properly restain a child or driving recklessly with a child in the car could be considered a comparable crime more on line with this situation.