It's interesting that you posted this and in the course of your comment mentioned the commentary aspect of Romero's work.
I was recently discussing with a close friend my firm belief that- if one were to remove the zombies from Romero's Land of the dead
and focus specfically on the cultural structure and sharp class division the director establishes within the framework of the film- you'd have a fair representation of where our own class structure is heading right now.
When both political parties were clearly willing to allow the country to go into debt default recently in order to avoid comprising either of their specific partisan agendas (particularly the GOP, which made blocking any attempt at raising taxes on the people who can afford it the most their rallying cry when almost forcing the default) , it was thrown into sharp relief that Romero's fourth dead film is startlingly prescient in its depiction of the grotesque separation between the middle to lower class and the wealthiest top percentile . Another decade of this sort of egregious cultural isolation of those closer to the poverty level by the ones farthest from it and Romero's socio-economic wasteland (which chillingly posits the absence of a healthy midde class altogether) is where we're headed in this society if things don't change.
Sorry,I know that's sort of off the point, but I had to put it out there.