Final answer:
The reason behind Dr. Stockton's friends making fun of him is not directly provided in the excerpts, but it may be associated with his behavior or characteristics that others find amusing or odd.
Step-by-step explanation:
The question about why Dr. Stockton's friends have made fun of him implies that there is a story or context surrounding the character which has led to ridicule. In literature, characters may be subjected to mockery for a variety of reasons such as eccentric behavior, failure to conform to societal norms, or an unusual event or characteristic associated with them.
The excerpts provided do not contain a direct answer to this specific question, so it can be inferred that the narrative might include scenarios where Dr. Stockton exhibited traits or behaviors that his peers found amusing, odd, or worthy of tease. Moreover, the passages discuss the theme of how people are perceived and the impact of labels, suggesting that Dr. Stockton's ridicule may be associated with perceptions and labels placed upon him by his peers.