Billy Budd was reluctant to believe that Claggart disliked him. The narrator characterizes Billy as naïve, but not unintelligent. He simply lacked experience, especially in dealing with people with evil natures. According to the narrator, this is common with sailors, who as a group "are marked by juvenility" and are used to following orders without questioning them.
The narrator definitively describes not only the inherent nature of Billy, but also of sailors in general.