The definition of God is flawed from a philosophical perspective. A being cannot be kind, omnipotent, and all-knowing. It is impossible within current logic and, therefore, should not be given any weight as a concept.
Could an intelligent being have created the world? From my little scientific knowledge, I should say it is, in theory, possible; however, I know enough to realize that even that is statistically improbable to the point that it should be disregarded entirely.
Atheism is either the truth or should be accepted as the truth due to the lack of any efficient evidence to suggest it is incorrect. Occam's Razor.
Reductionism has been proved scientifically superior to holism time and time again. It isn't wrong on this matter either.