Once a man has loaned you his slave, your ethics are bound to return the slave and not set him free.
Is that an extreme example? Yes. But it only takes one counterpoint to disprove a rule.
Only if you accept the legitimacy of the very concept of "slave" and that people can be owned.
Are you suggesting that you don't accept the notion of "ownership" of intellectual property such as books or music? Is your position that a book or a recording is like a human being that cannot be morally owned at all? If not, and you accept that these things can be owned, are you suggesting that the owner should not be allowed to place limitations on how his property can be used?