It would have been very unusual for a working-class man to be the dominant character in a room full of the wealthy upper class, indicating that there is something different about this mysterious inspector
The inspector says his evidence comes from a letter and a sort of diary found in Eva Smith's room, but this is a somewhat plausible reason for him to have all this information
Inspector Goole: '"We are members of one body. We are responsible for each other. And I tell you that the time will soon come when, if men will not learn that lesson, then they will be taught it in fire and blood and anguish."'
Priestley's opinions and the inspector's message can be seen as feminist, as Eva Smith's life experiences show how working-class women struggled in their society