Unchaste conduct is any conduct that is impure,unholy, and things that shouldn’t be mentioned among humans. It is anything that HUMILIATES ONE TO NOTHING! What does the issue of stealing make you feel? To me, it makes me feel that the person being stolen from is better than the stealer himself. That is humiliation!!
In some cultures, stealers are usually made to walk round their town and village naked with serious beatings following it. In other cultures too, thieves are usually burned or stoned to death.