When they call a crime by another name, they are usually trying bring attention to it in some way. For example they call killing your own mother is matricide because they are trying to say it is such a horrible crime. Regicide is killing a king or queen you owe loyalty to. Parricide means killing a close relative, and also implies extreme betrayal. Infanticide is an interesting word. In England it is when a mother who suffers postpardum depression kills her newborn. But infanticide is a lesser included to murder. The point being in this case that they don't want to condone that behavior, so they'll punish her a little. But they also realize she needs help.
