He fails at most things he does, but that doesn't mean he's a failure or a degenerate. He has good qualities about him and his reluctance to conform to social norms, what others perceive he should be, is more attributable to his hesitation than to him being a bad person. Take for example the abandonment of your wife and child. While most would consider this a cowardly and reprehensible act, it is not criminal nor necessarily indicative of his character towards others he cares about. You could also look at the predicament that Suttree finds himself in at the beginning of the novel. He wakes up imprisoned not because of any illegal or inherently wrong actions, but simply because he was drunk in the wrong place at the wrong time. Suttree is rebellious against the society he is supposed to be a part of, but does not transgress its laws or customs. It's more the questions of life and death, the metaphysical ones, that Suttree is most interested in