The answer to this question can be found at the beginning of the second section of this story, where we are introduced to Farquhar before his imminent hanging and told about his background. In particular, we are shown a figure who is desperate to distinguish himself in his support of the South but who is unable for some unknown reason to enlist and fight. Note what the narrator tells us about Farquhar's desire to fight in the Civil War and how he imagines the life of a soldier to be:
Circumstances of an imperious nature which it is unnecessary to relate here, had prevented him from taking service with the gallant army which had fought the disastrous campaigns ending with the fall of Corinth, and he chafed under the inglorious restraint, longing for the release of his energies, the larger life of the soldier, the opportunity for distinction.
We can see therefore that Farquhar imagines that a soldier, because of the opportunity that he has to distinguish himself, enjoys a "larger life" and therefore has a more heroic and satisfying existence. He compares the life of a soldier favourably to his own position, as he, for reasons unbeknownst to us, is unable to enlist.