Very intriguing!! “A horde of enemies for which there is no guilt when destroying them.” I’m probably over thinking this (in itself one of my hobbies),but in other words, the Zombies often represent a highly stylized ritual of desensitized survival methods.
A sublimation and homogenization of the LATENT BARBARITY INSIDE OF US ALL if pushed to the point of fight or flight.
I'd say that the zombie genre has become associated with certain facets of modern culture, but it didn't start out that way. Sure, the latent barbarity thing has always been there, as is the case with most horror tales. But yes, the "guiltless eradication of enemies" thing is a big selling point these days.