Free will. Because somehow the free will of rapists, child molesters, and murderers trumps the free will of their victims to, y'know, not be raped, molested, and murdered.

free choice

Just the old "devil made me do it" defense harkening back to the old SNL skits. Beyond that, they don't want to accept responsibility for their own mistakes.

Good cannot exist without evil like a balance of sorts.

Some of my friends are very New Age. A lot of people have thrown this weird Californized version of karma out at me. They'll literally claim that someone who's a victim of a violent crime was a criminal themselves ("in a past life," because of course), and thus they "learn" from the experience in this life. I've never got a straight answer on how this supposedly teaches any kind of lesson - seems to me it would be a bit like watching a dog mess on the rug, then hitting them with a newspaper two days later, and expecting them to make the connection.

When I was a teen, I asked that question of a priest and was told, Cain killed Able and that released evil into the world. I asked why God allowed that and was told...When God cast Adam and Eve from Eden he granted them free will. I asked if God is all-powerful, then why did he not destroy all evil and was told it was a test of man's faith. I said it sounded more like a science experiment to me and was told to go home and pray for forgiveness. Just one of the reasons I refused to attend church and that led me to question all I had learned.

Man has free-will and is influenced by Satan. It's all Satan's fault as God is 'good all of the time' (apart from when he doesn't bother to show up to stop 100% of the preventable tragedies, shame theists). I also love the Catholic 'original sin' version, how is that for messing up children and humanity.