The book ends with the extinction of all Jews, blacks, Hispanics, Chinese, Arabs, mixed-race people, liberals, conservatives, moderates, libertarians, communists, feminists, LGBTQ people, crossdressers, fetishists, sadomasochists, rednecks, interracial couples, the "unfit", "lesser" whites, and all white people who don't also hate the above... and yet a whopping 10% of humanity remains. That means that at the start of the book, as many as one in ten people the world over were genocidally xenophobic white supremacists! Probably even more, considering the likelihood of there being large swaths of white supremacists who still fell into one of the other aforementioned groups and who were thus exterminated along with everyone else. In such a world, humanity's extinction could be deemed a Mercy Kill.
Admittedly, it's possible if you fell solely into that last category but were savvy enough to hide it you could survive...not that you would likely want to.
Since the whole book is from the perspective of Earl Turner, there is the (very likely) possibility that he's distorting the events he's relating to the audience. It's possible the world he's describing isn't even a dystopia in the first place. For all we know, Earl and his goons might just be exaggerating what they feel is wrong with western society to justify their atrocities.
