Just for argument's sake let's say she was prostituting (trading sex for drugs). I haven't been raped by a man nor have I traded sex for drugs. Have you? They both seem like traumatic situations to me. The women I know that have been through those situations are TOTALLY ****** up in the head over it.
To answer your question, I think you are being judgmental and meddling in someone else's business. It sounds like her life is already ****** up enough.
Have you thought about ways you could help her? Maybe give her numbers of a friend in recovery? Maybe invite her to church?