Just a guess.
With the advent and now prevalence of photographs, how is it possible to do anything BUT objectify other people? In all honesty, I don't even think pictures are completely to blame for it, but more a derivative consequence. It's the Cartesian disconnect that we feel defines us as subjects, thereby alienating us from any real subject-subject connection. In a sense, we are even able to objectify our own mirror-image in that this "me" in the mirror is an other that the "I" sees.