Why is it symbolic that Wilson kills Gatsby?
"A blonde, spiritless man, anemic, and faintly handsome" man, George Wilson, with his pale blue eyes, is a product of the wasteland in which he dwells. He moves listlessly, trapped in his poverty and illusions and eventual hopelessness, outside the sphere of those who enjoy wealth and prosperity, and truly outside of reality. When Myrtle is killed, George cannot even determine who has been his wife's murderer.
Clearly, George Wilson is the counterpoint to Jay Gatsby. His tragedy is the tragedy of Gatsby: they both have loved a woman, who cannot truly give them love; for, she is imagined to be much more than she is. Both men are left with nothing: Wilson's life is meaningless and hopeless, while Gatsby spends the night "watching over nothing" as Daisy and her husband have
...an unmistakable air of natural intimacy about the picture and anybody would have said that they were conspiring together.
Wilson, therefore, represents the defeated spirit of Gatsby. With his pale eyes and ashen dust upon him, he is the shadow of what once has been a vibrant man, the walking symbol of an effete purpose, an effete love, and an effecte American Dream.