I've asked this question several times before (not necessarily here, can't remember if I did already) because I simply cannot be satisfied with the answer that is often provided, as though all of them are being dishonest, either just to me or also themselves.
Now when I write the title the way I do I did it on purpose. It is not enough to say that people want to be afraid of zombies. The most common reason given for why zombies are popular is because of the idea of how the zombie apocalypse appeals to fears in a particularly intimate way.
The thing is, popular culture is simply far too comfortable with zombies to actually restrict them to being horrors. It's practically a rotten fever for zombies the way there's a yellow fever for asians. You don't have zombie modes in FPS games, casual games like Plants v.s. Zombies that have obviously ridiculed the entire affair in the way people don't really take pirates seriously anymore, all sorts of ideas for preparation against a zombie apocalypse, and even people displaying manufactured zombie heads in their homes as stands for medieval helmets, because people are afraid of them. It would not surprise me in the least if someone wanted to french kiss the maggots out of a zombie cheerleader and then fuck her in the ass with all the moist, fragile, decomposing flesh serving as a novelty. Disease and decay is desired.
If you ask me, what's far more terrifying than zombies themselves are people that long for zombies. That applies to most reasons I am a misanthrope and this particular kind, where humans actively indulge in weakness through a particularly disgusting medium, is actually the first and most significant.
I did not want to hold human throats at knife point against jagged walls in the dark to ask them "What's the matter? What's the matter? Isn't this what you want? Don't you like being hurt? Don't you want to realize your powerlessness through being dominated? Isn't it great to know just how disgusting you really are? To be recognized and humiliated in your least dignified state? Don't you want your dreams to come true? Your dream of being sickening to the core, taking pleasure in just how helpless, insignificant, and desperate you really are? Or is it that you simply realize that I have not come to make your fantasies a reality, but rather to take away that very reality from you so that all those hopes to engage in such debauchery will expire?" prior to realizing the level of acceptance, understanding, and expectation humans have for those of such tastes.
Zombies in their most popular form are weak, ugly, slow, rotting, infested with vermin, without wills or intelligence beyond hunger for your flesh, have their strength only in great numbers and are thus commonly depicted as so, and convert others into becoming zombies themselves. Why? Why are there so many humans so very fond of them?