Final answer:
Bob Dylan was booed at the Newport Folk Festival for playing an electric guitar, which his audience perceived as a betrayal of the folk protest ideals he was known for.
Step-by-step explanation:
Bob Dylan was booed at the Newport Folk Festival primarily because he played an electric guitar. This was seen as a departure from his usual acoustic folk style, which was closely associated with the folk protest movement of the time. His fans viewed his use of electric guitar as a betrayal of the folk genre and its values, thus sparking a negative reaction during his performance.
Dylan was an artist who had become emblematic of social change, known for his meaningful lyrics and opposition to injustices such as the civil rights abuses and the Vietnam War. The shift to electric music at the Newport Folk Festival symbolized a change in Dylan's artistic direction, one that challenged the socially accepted norms of the folk community, and led to disappointment among fans who had specific expectations of his music and message.