That's their socialization. Among humans, there are subcultures
   that exist where "banging your own daughter" is perfectly
   logical, rational, reasonable, supported by what they consider
   evidence. Does that make it right? I don't think so, but I'm
   speaking from the culture/subcultures from which I was brought
   forth.

   Look at pets and their relationships not only with humans but
   with fellow animals in the same house.

   How is it that I have cats and dogs in my house that get along
   with each other?

   In the wild, they'd likely rip each other apart.

   They're not in the wild. They're domesticated.

   How is it possible to domesticate?

   If you believe it is inhibition of instinct that causes
   domestication, then you have to follow the line of BF Skinner's
   reasoning and research: That we are all animals and no different
   and are domesticated human.