I think people tell their children to fear them because they want them to in turn fear becoming them. I could understand being fearful in specific situations but people do let it get in the way of making good decisions about how to handle the situation. Like needle exchange programs for example, it's been shown that they are beneficial yet people just don't like the idea of them.

People want to justify not helping them so they tell themselves the addicts got themselves in that situation and it's their own fault. There are people who think if we just got rid of all the drug addicts and demonized it further it would stop. Despite the fact that we can look at other countries and see what does work. If these people chose to see an addict as a person, they would have to accept that they are the type of person who thinks "getting rid of" sick people is a good idea. People want to believe they are good and compassionate people so they dehumanize the addict. Just like how we dehumanize Hitler to avoid accepting that humans are capable of evil.