Failure to imagine what it's like to be someone else, from a different place, a different time, with different ways of thinking -- is perhaps the biggest reason why we have so much violence and hatred in this world, and modern scholars are just as guilty of it as warmongers and propagandists of the past have been.
It is a failure of imagination, a failure of empathy, that every culture encourages -- sometimes subtly, but often not so subtly -- in order to keep its members loyal. One of the defining characteristics of human cultures is that each wants to have a monopoly on a person's mind.
Most of us grow up believing that their way of thinking and living is the only natural way, and parents and teachers rarely try to give us a world view that goes beyond what's considered mainstream in our own cultures. Having lived in a cultural greenhouse all of our lives, the first thing we do when faced with a radically different way of life is how different this other person is. The differences so overwhelm us that we forget to appreciate our common humanity, with all its greatness and weaknesses, that should be the first step towards truly putting ourselves in the other person's shoes.
It would seem that anthropologists and archeologists are no exception.
Is it repugnant to kill innocent children at the altar of some imaginary being? Of course it is. Is it a necessary trait of civilized people that they cannot bear to imagine themselves growing up in a culture that practices human sacrifice as a matter of course and learning to participate in the bloody rituals? No, it isn't. It's just a failure of imagination that our own culture encourages. We have learned to be unable to imagine ourselves performing such terrible things, just like Victorian culture made it look normal for young women to faint at the slightest sight of anything disturbing. The inability to "fathom" another culture, no matter how seemingly barbaric, is not so much evidence of the moral depravity of the other culture as it is a testimony to our own narrow-mindedness.