I think you've misunderstood what Lynne means. She's employing the 'original sin' argument - which goes like this: God made the world perfect for mankind, and all he asked in return was that mankind should stick to a few simple rules. Mankind didn't (in the metaphor, Adam and Eve ate of the fruit) and so God said, "Right - just for that, I'm going to let Satan take a shot at you, and then you'll have to make decisions about where your loyalties lie."
So she's not saying that each individual's mentality affects stuff like leukaemia. She's saying it's inherent to the human condition that God allows Satan to impose suffering on us, and that's no fault but our own.
All that's not, though, an argument for the existence of God, because the situation as stated requires the pre-existence of God in order to be possible.
Me, I think that a God who gives people curiosity and then puts them in a garden that contains a tree they can't touch is just asking to be disobeyed, so if that's how it happened, I'd say God was as much to blame as Adam and Eve. If it were a court case, he'd be charged with contributory negligence.

