I guess technically they are not zombies in the hollywood sense but in the Voodoo sense they are as they only appear to have died but are actually just tranced. In fact if you follow some of the links in the first article you posted there are accounts of people spending several years as a zombie and waking up to discover that not only have they been used as slave labor they were at one point buried and thought dead.

The most intriguing thing about the article is the means of creating zombies and it leaves off the rabies style virus which is the core of one zombie movie. Each of the 5 methods in which real life zombies could be created will create living zombies, though they are robbed of some or all of their higher functions.

The argument to dispel the possibility of zombies all assumes they are both deceased and the only means of communicating the condition is through bodily fluid transfer. Many viruses can lay dormant on door knobs, toilet seats and other commonly used items. Many viruses and bacteria have long dormancy periods, some even decades. Others take so long to reproduce and or demonstrate any symptoms that much of the population is infected and don't know it. HPV for example. More than P of the US population has it. Most people never show any symptoms. For women it raises their risk of cervical cancer dramatically but takes many years normally to impact her health. Both sexes will sometimes have wart outbreaks associated with the disease.

Think of a mad cow or rabies type payload combined with a HPV, Encephalitis type delivery system and dormancy period. In a single year you would see AIDs type infections going on. Before the virus strain could be isolated millions of infected could be running around. It could be transmitted sexually, potentially through insect bites, through bodily fluids, blood transfusions, could potentially cross infect species such as dogs, pigs, cattle and could wind up in our food supply in ways similar to mad cow disease, and of course through direct bites. Rabies for example is wonderfully adapted for crossing species lines. Almost any mammal can get it. It has a short incubation period or it would be a much larger problem than it has been.

If the virus had multi-stages it could be both fast and slow infected. The actually bug crazy eat your brains types might turn a bite victim into a zombie in weeks or months where as sex with the infected or sharing a cup with the infected might take years.

More so, the slow moving might well be a total myth. Just because they are disconnected from their reasoning circuits doesn't mean they cannot be cunning. Zombies infected through many of the 5 methods described in the first link would possess full faculties when it came to hunting prey and might even retain enough cortex to operate machinery, drive and use weapons. They would feel pain and would have an instinct for self preservation. So the big myth is not the possibility of them happening but the likely hood they would at least in early stages be shambling wrecks. Later stages of the disease would likely destroy more and more of the brain until they eventually did become literal undead and once bodily functions ceased they would likely succumb to the elements. Though the capability to continue to attack long after the heart stopped beating would be terrifying and cause major morale problems among the uninfected.

If the infection was large enough, came from a source such as say soy where  of the population would be infected in short order. For example genetically modified soy produces a toxin which shuts down the immune systems ability to target a specific virus/fungus/bacteria. One which humans have long since gained immunity too but which is so pervasive it's a normal part of human fauna, just in quantities too small to infect a person. In short order a huge percentage of the population could become infected. Bites and other bodily fluid transfer including rape (reproduction instincts would likely persist long after reasoning ceased) would inject high concentrations of the virus into a body possibly causing infections that overwhelm the immune system. Thus a zombie apocalypse that happens almost overnight and impacts most of the world.

Zombies in fact might well be able to reproduce if pregnant women were able to survive long enough to both give birth and to raise a child to at least 5 or 6 years old. Old enough where they'd have some semblence of a chance of survival. Motherly instincts are at the core just that, instincts. Language and tool use would have to be learned from example as those tend to be higher reasoning but nursing and basic child rearing could be accomplished though with very high mortality rates due to poor sanitation and environmental factors including possibly predation by other zombies.

As such the 7 reasons why zombies couldn't happen really don't apply except to the recently deceased zombie assuming they are capable of movement at all after death.

Some very interesting real life examples in the insect world.

http://news.nationalgeographic.com/news/2011/03/pictures/110303-zombie-ants-fungus-new-species-fungi-bugs-science-brazil/#/zombie-fungus-infects-insects-mind-control-early-infection-ant_32852_600x450.jpg

http://news.nationalgeographic.com/news/ 2005/09/0901_050901_wormparasite_2.html

A couple disturbing links as it's not out of the question for such things to spread to Mammals and Reptiles.

Correct, 5 Reasons it could happen and 7 Reasons it would fail quickly, and from what I can see, there are more reasons it would fail quickly than sustain itself.

Would you really want that kind of life? Spending every moment wondering if you will live to see dawn. Having to kill creatures that were former members of society. Would you be able to live with yourself knowing that you just killed what was once your neighbor, or even your family?

Would you be able to kill fellow human beings (Because people will try to kill you, be it for your food, supplies, guns, etc.)

Not to mention the fact that for a zombie apocalypse to occur, billions would die. Chances are, you would too.

Now, let's say that all this does happen.

Do you have a gun?

Do you have access to a good source of supplies (And don't say Walmart, because most people would say the same (Imagine a Walmart crowded with people, many of whom may be infected, and all of whom are fighting for their lives.) )

No offense, but do you really think so? Game and reality is different.

Source ?