The "faceless horde" angle is still in line with the "other uprising" allegory. Day of the Dead's predecessor, and the origin of the modern zombie in pop culture, had fairly overt racial undertones, and its sequel, in its concern with barrier-breaching ghouls, made plain the nationalistic undercurrents by setting the action in a military bunker.

There's really no getting around the influence of real-world race and class attitudes in shaping zombie fiction.