Zombie Apocalypse/Analysis
Common to virtually all Zombie Apocalypse tales is that, regardless of the reason zombies attack living/non-infected people, they never attack other zombies. This makes some sense in stories where the zombies are manipulated by some force intent on attacking humanity, or where they need fresh human meat to survive, but it occurs even in films like 28 Days Later where The Virus is just supposed to make the infected vastly more angry and homicidal than before. Why they never turn on their own is rarely, if ever, addressed, although sometimes they can be seen fighting for food, but this never goes beyond pushing each other out of the way. This can be subverted if ordinary humans can avoid being attacked by pretending to be zombies.
Any truly large-scale zombie apocalypse is likely to demand a heavy degree of Hollywood Tactics or Idiot Ball by the military. Against any sort of heavy or explosive weaponry, the unprotected human body is not simply wounded, but ripped apart. For that matter, armored vehicles like tanks would be completely invincible against an unarmed foe, and weigh enough to crush bones merely by running something over. Rarely will any of this come into play. There is some justification under the Romero rules as any death renews the problem, and quite possibly within a secure area. Depictions where zombiism is The Virus may avoid the issue by noting that, eventually, the problem is contained and dealt with. In World War Z, there is an attempted Hand Wave along the lines of zombies not feeling pain or fear, and the military caring more about looking good for the media, but at best badly underestimates the ability of modern ordnance to blow organic matter apart wherever it hits.
Overwhelmingly, zombie apocalypse stories tend to fall into one of two categories of political allegory. The zombie horror can be used to make a political statement against capitalism and consumerism, with zombies representing the bulk of humanity as unthinking (flesh-eating) sheep (zombies in the mall, anyone?). The other strain of zombie horror advocates hardcore individualism and libertarianism, again with the zombies as the "unthinking masses", but with an added emphasis on the heroic "well-prepared" survivalist, with Karmic Death to anyone who dares show compassion for others or cares about anything other than their own personal survival. Strangely, though zombies seem to fit the Aliens-As-Communists archetype, pro-capitalist, anti-communist zombie apocalypses are less common—and anything that would be considered patriotic is right out; the military is never anything but an obstacle at best, more often actively evil.
Often, zombie apocalypse stories are tied with a Science Is Bad message, or an allegory about human nature. (Night of the Living Dead contained an allegory for race relations, though Romero stated that it was unintentional. Its sequel, Dawn of the Dead, skewered American consumerism.)
The Zombie Apocalypse is so iconic that perfectly sane people will formulate emergency survival plans in case of shambling corpses. There are also survival guides available all over the web and in print. The explanation occasionally given for this is if one is sufficiently prepared for the complete collapse of societal order and infrastructure and the almost spontaneous appearance of unending hordes of hostiles with a quick and simple method of conscription, one is effectively prepared for anything. Actual rescue agencies will sometimes have "Zombie Apocalypse" training exercises because it allows the people to brainstorm freely without causing political turf wars or falling into routine ideas (and because professional rescuers have dark senses of humor). And be honest, you know that you would secretly love for one to happen.
Zombie films have an ace in the hole for directors, too. The monsters are cheap. While you can use CGI, etc for them. all you really have to do is hire some extras, throw makeup on them, and voila! -Instant monsters.
In reality, this situation is highly unlikely. A week-old corpse on a pleasant summer day, moving or no, will be fertilizer by evening. It's also rather like going up against a bear every time you want to make a sandwich or mate from the perspective of the zombies, as their preferred choice of food and reporductive medium is also their greatest predator. And, as it has been noted in the quotes page, Humans send robots to other planets, while zombies are befuddled by doorknobs and stairs.