God doesn't prevent terrible things because?

[BlkPaladin]

E. He will once there is enough irrefutable evidence that man cannot rule himself.

This goes all the way back to the original sin, which wasn't sex, he told them to fill the earth with their offspring so how could the original sin be sex. The core of the original sin was the challenge that God had no right to rule, or specify what was right or wrong for the humans. Of course he could of just done away with the traitors on the spot but didn't because it would leave the accusation open. So enough time had to be set aside so humans and the being that became Satan (which isn't a name but a title meaning resister) could try as many forms of rulership. But at the same time he instituted the first prophecy on how he was going to redeem mankind.

The book of Job covers a similar accusation, and insight on why God allows that Satan brought up that Job only worship god because god protected him. God allowed Satan to cause all sorts of calamities to befall him. And once Job demonstrated that he wouldn't falter in his faith, he not only restored everything he lost but gave him seven times more.

So God has promised to do similar to mankind. Not only will he restore the earth and resurrect the faithful. He also promised to resurrect those who didn't have a chance to prove themselves faithful because of time and circumstances. (Acts refers to this as the resurrection of judgement.)

The question is actually a rather deep question, its at the core of everything the bible teaches, that has more meat to it than that and I could spend a lot more time on the subject. But that answer should suffice.