Spike,
"Nonbelievers" aren't all of one type. "Fault" doesn't have just one root. "Rejecting" is not for only one reason. "God" is not only applied to the Bible's "only true God". The answer, thus, to the question Is the Nonbeliever at Fault fo Rejecting God? thus depends on the context of the question.
Wow, that was really good. I enjoyed your reasoning about the question's being non specific enough to answer, all though the context would seem to imply the biblical deity as he is often shown to be jealous when it comes to his worship and acknowledged existence, by the human species, and making it a matter of salvation.
Granted the human mind and its tendency to project(transference) its common feelings and insecurities onto it's worshiped deities(or creating gods in their image or Anthropomorphization of a god's looks and feelings). And so jealous and violent deities have been somewhat common especially back in the days the books of the bible were being written. Today I think we are seeing a trend in God's projected or assumed thoughts and feelings towards a more loving and peaceful deity that doesn't quite match up with the ancient biblical deity(a different period in man's ideological development)
My view of course is that a creator of everything in the universe teaming with billions of galaxies that contain billions of stars(many with planets with many different forms life on them), would be too inundated with other concerns to be messing with some humans over whether or not they acknowledge his greatness or existence by a reward system designed to favor the pious, and execute or somehow withhold rewards from the non believers.
If we can some how step away from our common tendency to make our world view god's world view(transference)er ask: Why would god even care who worship him if he is free from egotistic desires?