The Torah is only about the correction of the desires. Slavery is when one desire belongs to another stronger desire that can correct it. So in ancient times people lived a collective, social life.
“My daughter” is the desires that I discover but which I cannot correct by myself. I cannot marry my daughter; I cannot give birth to the next levels of my offspring. So by developing my desires, I don’t connect to the desires called “daughter” as a father, I don’t come to her with my Masach (screen), since another Masach has to control her, another desire. This means that she belongs to another. I sell her so that she will belong to someone else.
Therefore it says that “she shall not go out as the menservants do,” since the female desire should belong only to Bina where it is.
From KabTV’s “Secrets of the Eternal Book” 3/11/13