I get SO mad...

Just about every day, I read a story about a parent abusing, neglecting, or even killing their own children.  It makes my blood positively boil.    I realize there is often mental illness involved, but it doesn't change the fact that lives are lost so senselessly.  There are so many parents in the world who are completely broken by losing their children...and then there are those that are robbing their children of life by choice.  How can this possibly make sense?  How?