That would bother me too. It sounds like these people need more training on the wider issues surrounding substance abuse issues. If they are that negative perhaps your employer/boss or human resources should bring someone in to do a workshop with them and address the lack of sensitivity. I think it would also help the children who these people work with as their attitude will ultimately filter to them in some way even if it's subtle comments. It won't go unnoticed by those children. And no matter what these kids have been through they will always want to love their parent and that should be respected.