In the movies, you often see a completely horrendous person loved by a beautiful woman who is completely aware of the villain's proclivities which might include murder, torture, kidnapping, drug dealing, and so on. The lovers often turn away from the activity as if they do not support it, but they still love the villain. These lovers invoke sympathy from the audience and often the heroes of the story. This seems to be true in real life as well, following the fallacy that you can't choose who you love.
The person who loves a villain is a BAD PERSON! If one loves a horrible person and does not do everything in one's power to bring him her or her justice, one is a horrible person, too! The lover is just as bad if not worse for encouraging and enabling the behavior of the horrible people they love.