Lots of people turn their lives around without the JWs. People are basically good, anyway. There's AA, NA and other groups that people go to for help to change. There are counselors, therapists, and rehab that people go to for help. Some people have found the fortitude within their own selves to change. These people never needed the JWs to do that.
I still think I'm a very kind and caring person without the JWs. I do speak my mind and think my own thoughts now, so maybe that makes me evil in their eyes because I am a free thinker and not a robot.
I don't smoke; but just because someone smokes, it doesn't make them evil. Lot's of good people smoke. Smoking isn't a healthy habit, but it certainly isn't the evil demonistic practice the JWs claim either.