One of the character traits of a Libra is being charming, but as we see in the first couple chapters of his story, Lee is the total opposite. He goads people on just to get into a fight, he knows he's smart, and he's not afraid to tell other people about it. He would have done well at Uni.
Libras are also supposed to be diplomatic, and handle things with grace and dignity. And yet, when Lee gets picked on by other Marines, he acts out in every possible way. In an attempt to stay at Japan, he shot himself in the arm. When Reitmeyer tries to mess with him, he almost cries out of frustration. That doesn't say grace or dignity to me.
So what does it say about the book that the title is so starkly opposite one of the main characters?