Yeah - the Walking Dead doesn’t seem to fit science fiction. As it is SO outlandish. Until I read an article about some wasp that stings some sort of spider, and the spider spins a web like it has never done before - and it is a nest for the wasp! (Zobie-like behaviour!).
Then a freeper educated me on rabies, and how that makes a person unable to drink water. The virus knows it will weaken the sickness, and so it causes the brain to be water-phobic! No matter how thirsty one is, you can’t drink the water!
One could add to this and “explain” the zombies in much the same manner that the huge insects of the 1950’s films were “scientifically” explained by radiation. (In a health and safety class the guy said “Um - you’ll be dead from the radiation sooner than you can grow 10 feet tall, or pass off two noses to your children.”)
Yes, back when I was a pup in school, science class I think, we were taught about a disease called hydrophobia, which today is called Rabies. Back then it was sometimes referred to as rabies..but the disease was hydrophobia then.