Near as I can tell, it's just another symptom of the direction society at large is headed. Life is no longer held in much reverence any more.
These shits see someone happy at the prospect of a new life coming into their "sphere" and they seek to fill their own empty, meaningless life with that happiness. So they take the baby, on the (erronious) assumption that the baby was the source of it's mother's happiness, it'll surely make this worthless shit happy too.