Y'know what? I know you're all freaking out right now because, 85.9% of the way through the story, I'm suddenly throwing in a zombie apocalypse... but I'm going to take a moment here to talk about the movie Fight Club instead.
I'm going to give a spoiler warning here, in case you aren't already familiar with a seventeen year old movie. Go, see it, then come back.
And yes, yes, I know, Fight Club is a book too, you're very smart, but the vast majority of people who are familiar with Fight Club are familiar primarily with the 1999 movie in which Edward Norton's nameless protagonist is possessed by a demon and starts an evil cult that is ultimately responsible for the deaths of thousands of people.
Oh, did you not know that that's what happens in that movie? Well, here, let me break it down for you.
Jack (fuck it, we're calling him Jack) has various mental problems, yes, but nothing that would jive with either current understandings of dissociative identity disorder or classic movie-style multiple personalities. No, Tyler Durden slides into Jack's mind disguised as a penguin, an entity from outside of Jack's self that enters Jack's weakened brain while he's engaged in meditation (heathen mysticism, you see).
This demon (much like some politicians I could name) knew that the best way to amass a group of devoted followers would be to appeal to a majority, ideally the same majority to which Jack himself belongs - nonmillionaire men.
And yes, I know, women outnumber men, but they tend to have less independence and less aggression and overall they're less susceptible to this sort of crap stop interrupting me.
Tyler's first move is to attract men to an underground boxing club. Boxing, after all, has been popular for millenia, and can be done by virtually anyone. It angries up the blood and gets people excited, and it's superficially similar to but isn't the same thing at all as actual violence - there's only so much damage a human being can do with their fists.
Once he has his audience, step two is to isolate them. Rich, upper class men would be unlikely to attend meetings in filthy basements, and the less-quoted sixth and eighth rules effectively ensure no female members. And, once you have a secret club of lower-class dudes (most of whom have about as much romantic success as they do financial success, and therefore no families to pull them back from the brink), it's easy to create a subculture of simmering dissatisfaction with both a) women and b) The Man (a simmering dissatisfaction, you will note, that does not make them any more attractive to either romantic prospects or more lucrative employers).
From there, you can easily begin step three - preaching to the choir, telling these angry men exactly what they want to hear. The world is unfairly stacked against them. Only they know the way things truly are. Rich men are lying bastards and women are the resources they control.
(As a side note - how, exactly, do you think Tyler would have threatened the police chief if she'd been someone who didn't have balls to cut off, hmm?)
Anyway, step four is to radicalize the club into Project Mayhem, to tip them from words to actions - simply done, once mob mentality has taken effect.
Oh, and backing up the "demon" motif, note how the whole operation is financed with human flesh and marked with desecration of human anatomy for essentially no practical reason.
So, once one has a cult to control, what's the easiest way to hurt the most people - to cause the greatest sum total of human suffering, in the short time you have before the whole mess falls apart? Well, why not wipe out their bank accounts?
And make no mistake, destroying those buildings may, indeed, delete a lot of bank accounts, (with both positive and negative balances), but one thing it would not do is topple the entire structure of modern capitalism. In fact, large companies like Citibank and American Express would probably be just fine in the long run, cashing in billions of dollars in insurance policies, lobbying the government for bailouts and new legal protections, staffing all their future facilities with armed guards, and, inevitably, trickling all those costs down to the consumers.
Consumers, it should be noted, who still need credit. Consumers who need to buy houses and cars and college educations, and likely don't have thousands of dollars in physical cash in their piggy banks to do so. Consumers who will likely still accept whatever hunk of plastic promises them instant gratification and Air Miles in exchange for whatever the new, slightly higher, interest rate is.
And the deaths I mentioned? Well, there'd be three causes.
The most obvious ones would be immediate - despite Tyler's insistence that the buildings were vacated, as we all learned two years after that movie came out, the unplanned and chaotic demolition of skyscrapers in the middle of major cities tends to have some side effects.
The second cause? How about the millions of people who wake up one morning and their credit cards don't work, and their bank accounts don't work, and they need things, like, say, food or transportation or shelter or medicine to live?
Oh, and let's not forget the third cause of future human suffering and death - major news-worthy terrorist attacks like this will necessarily lead to increased police and anti-terror militarization, which inevitably will lead to (both rightful and wrongful) raids and arrests and shootings.
Once his desperate attempt to stop Project Mayhem has failed, Jack shoots himself, and Tyler leaves - not because he has been defeated, but because he has won. Tyler no longer needs Jack or Project Mayhem. The detonations go off as planned. Tyler, the demon, has caused absolutely titanic human suffering, and no doubt will be handsomely rewarded once he returns home to hell.
And the real tragedy of this tragedy is that so many fucking people don't realize that Tyler Durden is the fucking bad guy. His transparently misogynist and classist and ableist and nihilist rhetoric resonates with his target demographic, both inside and outside of his fictional world. Dipshits think he's cool. Dipshits think he has a point. Dipshits probably think that Project Mayhem successfully erased debts, making the world a fair and poverty-free place. Dipshits probably think that a panderingly populist, destructively anarchic movement led by a single madman with virtually no democratic feedback or diversity of opinion can make the world a better place. Dipshits probably think that rancid fat stolen out of a dumpster can make decent quality soap.
In case it wasn't already clear, I dislike the movie Fight Club (and no, I don't give a shit if the book was better, nobody gives a shit about the damn book). I don't dislike the acting or the cinematography or the script or the music. Artistically, it's a damn fine film and is very entertaining. But, like Atlas Shrugged or Birth of a Nation, it has a terrible cultish central message that is persistently embraced by dipshits.
And about the only thing it gets right is that yes, if you angle it just right, and get really lucky, it is possible to survive a point-blank gunshot to the head.