If a dealer correctly determines that crack will keep a person interested, and that crack is, let's say problematic, isn't that an issue with the person not the crack?
We appear to be arguing over semantics. The points being raised here are variations of the following questions: how much is a human life worth, and whose responsibility is it to preserve that life? If you want to poison yourself, is anyone under any obligation to stop you from finding or giving you that poison?
It actually is, children are more raised by society than parents in general. Overall the environment has much more influence on children than the parents, that is societies job to make good environments for children, that is way too much for parents to handle.