The simple truth is that we know for a fact that humans have messed things up in past, present and will in the future. We do not know to what an extent God has ever messed things up. So for me it is indeed more credible that even the most unthinkable bad stuff might potentially be due to human mess-up and neglect, rather than God's. God intended the world to be a paradise, but we all know that humans had different agenda.