How can you NOT care?

Have you ever read The Stranger? Let me tell you, it's one of the most disturbing books I've ever read.  I don't think I even got through the whole thing.  But still.  I have read some pretty disturbing things too.  Gory murders, people turned into lard, child abuse.. and yet...

How can people not care about things? I think to a certain level I understand.. I mean up til a few hundred years ago people actually had to work work to make a living, and they didn't have the luxury to just do things.  In The Stranger, Meursault just does things.  He lives.  He's almost like a parasite, just living off the infrastructure that other men have built up.  He's a bum living a bum life and basically he decides nothing matters.  He gets engaged, kills a man, and gets pushed around by other people because he will do anything people tell him to do.  And in the end, the guy who believes nothing matters dies for his own freaking cause! Doesn't that mean that he believes something really DOES matter? Nihilism is a cause in and of itself, is it not? 

Apathy bugs me.  It digs deeper than violence.  It digs deeper than.. evil.  It's like an evil unto itself.  I don't get it.  I don't want to get it.  I don't want to live in a world without right and wrong.  I like rules.  I like morals.  I like believing my life will be worth something, in the end.  

I wonder if Meursault cried as a child.