It's hard for me to comprehend as well. I went through (and am still going through) very severe post-partum depression. Some days it's really hard for me to interact with my baby because all I want to do is cry. I don't want to play games with him, I don't want to sing songs to him, I just want to put him in his crib and sleep for a while. But even on those days, I still care about him. I still want to make sure he's clean, well-fed, and safe. I'm guessing that hams care so little about their kids because of their "me me me" attitude, coupled with the fact that they are incredibly lazy and don't do any actual parenting.