Gold Digger sounds too nice.
Waste of flesh, Leach, bad parent, pathetic... I can't seem to think of something proper. None of them quite capture my disgust, and utter rejection of their forsaken right of existence.
Possibly, with all of the above framing in mind, the word sheep, or some other livestock, might fit.
Is there any hope for them changing, learning, at all? I really hope so. Though I dread the drain on our economy and the cost of that lesson. There must be a better way of discouraging such decisions.