Because he is just not quite omnipotent enough. Mainly because he only exists in people's imaginations.
You ever hear the phrase "You can lead a horse to the water but you can't make him drink it?" God's most likely tried to reveal himself to these people, but they write it off with things like "Oh it's illogical" or "It's just you -wanting- Him to be real, spiritual experience explained!" And if he manifested on live TV, he'd probably kill us.
We cannot grasp the true form of God; it would literally blow our minds and we'd go mad or think it was something else, since our minds cannot comprehend His full on presence. As for miracles/signs, Jesus said he wouldn't even perform miracles to a crowd of people who wanted him to do it JUST to prove he was the Christ.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.