Zombie Related: Why is it...?

Any zombie film or TV show or game I've ever come across that has a "real world" setting always has one gaping hole in overall logic.

Whether it's Dawn of the Dead, 28 Days Later, Zombieland, The Walking Dead, Resident Evil, The Crazies, Shaun of the Dead -- the list is pretty long -- there never seems to be any outright acknowledgement that zombies have been a part of popular culture, in films, books, video games, legends, for a long time.

Zombies? Never heard of 'em!

Wouldn't it make sense in these movie universes that people have seen zombie movies before? Shouldn't they just know that they should avoid being bitten and aim for the head? That they'll follow loud noises? That zombie are essentially running on the basest of instincts and react predictably to a set of stimuli? Wouldn't the characters understand any of that?

Apparently not.

Any piece of zombie literature, film, video game exists in its own bubble where no one anywhere has ever had dealings with zombies before. (Unless it's a sequel.)

And for some reason this really annoys me.

Or am I just not paying enough attention for evidence to the contrary?