People who use them to inflict harm left and right are using them for the wrong reasons. I can also guarantee to you that I am less likely to get in a situation where I need to use my fists now that I know martial arts and know I can basically stand my ground and repel ANY attacker, than before, when fear of physical danger was present and I had no means other than trying to be smart to defend myself. However, say you're in a bar, and someone decides you're in their seat. Martial arts can certainly save you in a situation like this. And just so you know, usually martial artists are taught not to strike until teh other person throws the first blow.
Violence is a last resort, martial arts are more than violent moves.
If you run once from an abusive situation, say you're a woman, your boyfriend beats you. Usually people say run away from him, end the relationship. Knowing a little more than street smarts will be necessary. I definitely support women who take self-defense courses, especially if tehy live in big cities. Learning how to land a good kick in the groin is not really a natural thing.