When Piggy reveals the name the kids at school called him, he is placing his trust in Ralph not to tell anyone else. I realized that this trust in Ralph was a mistake when Ralph started laughing at him and then later told everyone that his name was Piggy. In the book it says that Ralph "shrieked with laughter" and "dived in the sand at Piggy's feet and lay there laughing" (11) when Piggy told him what they called him in school. He had already begun to make fun of Piggy when he knew that he was ashamed of his nickname and felt embarrassed and hurt. Ralph later told everyone Piggy's name, despite Piggy informing him very clearly that he did not want to be called that. Ralph cried, "He's not Fatty, his real name's Piggy!" (21). Everyone then began to laugh at Piggy and make fun of him, causing Piggy to be embarrassed yet again. Ralph betrayed Piggy, and when he was confronted about it he said "better Piggy than Fatty", and left him without another word. I was extremely surprised that Ralph mishandled Piggy's trust, especially because they were the first two people that found each other. They were the ones who organized everyone together originally, so I figured that they would become friends and stick up for each other. I thought that Ralph would respect Piggy enough to keep his secret and not make fun of him like everyone else.
I infer from this that Piggy is slightly paranoid and sheltered. This is evident even before this passage. Piggy would not participate in something like swimming in the lagoon with Ralph, and his excuses would always start with "My Auntie said..." part of this is to blame on his Aunts side because she seems to shelter him from the world. Because of Piggy's up bringing, it makes him vulnerable in a civilized setting, but in a setting where he is stranded on an island filled with people who don't seem to care about him makes him ten times more vulnerable. I infer from this quote that something tragic will happen to Piggy, whether it be at the hands of the other boys who don't think fondly of him, or at his own hands because of being sheltered and letting himself stay sheltered.
This quote is significant because it quickly characterizes Ralph well. Ralph is a very insensitive person, especially when it comes to things that aren't about him. The fact that he would even consider taking the path of "further insult" says something negative about his character. For most people, apologizing after betraying would be the default option, but for Ralph, he actually had to consciously decide between that and bullying Piggy further. Even after confronted by Piggy, he brushes it off as best as he can. "'Better Piggy than Fatty,' he said at last, with the directness of genuine leadership, 'and anyway, I'm sorry if you feel like that. Now go back, Piggy, and take names. That's your job. So long'" (25). Basically, Ralph is implying that he what he did wasn't all that bad, enough that it could even be seen as a favor. He even has the nerve to keep calling him "Piggy", even though Piggy has expressed his obvious discomfort with the nickname. Ralph doesn't even take a second to try to sympathize with Piggy and instead dismisses him with a clear conscience. Overall, Ralph's current characterization, especially from this quote, doesn't paint him a someone who doesn't really think or care about how his words and actions affect others.