What does the quote "He drove down N.M. 53 toward Zuni a little faster than he should, the mood bothering him because he could find no logical reason to explain it. Why resent this assignment?" Mean?

In taking this job, Leaphorn is assigned to a task that will involve immersing himself in a murder investigation between two cultures that are involved in a longstanding feud. The feud, between the Zuni and the Navajo. Like Leaphorn, the suspect is a Navajo, and he has been tasked with finding him. Chief of Police Pasquaanti is Zusi, and the murder took place on Zusi land. As a result, Leaphorn is questioning his task, but he isn't quite sure why. As readers, we can infer that he feels torn by being given the task of apprehending one of his own culture..... questioning, why me?