What does “class” mean in society? For example: lower class, middle class etc.

Read this excerpt from "a visit from the goon squad."that’s when he began singing the songs he’d been writing for years underground, songs no one had ever heard, or anything like them—“eyes in my head,” “x’s and o’s,” “who’s watching hardest”—ballads of paranoia and disconnection ripped from the chest of a man you knew just by looking had never had a page or a profile or a handle or a handset, who was part of no one’s data, a guy who had lived in the cracks all these years, forgotten and full of rage, in a way that now registered as pure. untouched. how does the author use satire in this excerpt? the author is criticizing media censorship. the author is criticizing the idea of isolationism. the author is mocking society’s overuse of technology. the author is mocking man’s inability to freely express himself.