In any good zombie story, the zombies represent the weakness of a society or community of people they come after. Zombie films are therefore allegories. In Night of the Living Dead, the zombies tape into anxieties of the late 1960s — the dehumanizing violence of the Vietnam War, uneasy reactions to the Civil Rights movement and a human tendency to become as monstrous as any monster who attacks us. With each subsequent film, the allegory gets updated. Land of the Dead is about brain-dead consumerism.
The late 2000s and 2010s saw the humanization and romanticization of the zombie archetype, with the zombies increasingly portrayed as friends and love interests for humans.
Notable examples of the latter include movies Warm Bodies and Zombies, novels American Gods by Neil Gaiman, Generation Dead by Daniel Waters, and Bone Song by John Meaney, animated movie Corpse Bride, TV series Pushing Daisies and iZombie, and manga/novel/anime series Sankarea: Undying Love and Is This a Zombie?
In this context, zombies are often seen as substitutes for discriminated groups struggling for equality, and the human–zombie romantic relationship is interpreted as a metaphor for sexual liberation and taboo breaking (given that zombies are subject to wild desires and free from social conventions).