According to some theories, there has been an increase of "zombie" movies since 2001. This coincides with the "War On Terror", where some theorists believe zombies are symbolic of Islam and/or Islamic terrorists who aren't as concerned with their own well-being as they are concerned with killing others not like them (i.e. infidels), or converting others to their ideology (in the fact that the zombie virus turns infected into zombies).
For the record, Zach Snyder has never (to my knowledge or exhaustive search) indicated that this was the intent of his remake, and as we all certainly know George Romero's original symbolism was aimed at mindless consumerism. However, enough people have commented here about Islamophobia so that this view at least deserves some attention. And, Zach Snyder has, on multiple occasions, stated that "A good zombie movie has to have social commentary in it", so it's completely possible that, given it was released 3 years after 9/11, that was his social commentary.
For a few links where people believe this was a direct connection to Islamophobia, see:
American society, it is not at the forefront of its subconscious, nor
is it what gives Snyder’s remake its terrifying appeal. By reinventing
Romero’s zombie as a fast-moving, highly dangerous and contagious
organism, Snyder has embodied the media’s portrayal of fanatical
Islamic terrorist organizations such as Al Qaeda and ISIS in the
zombie. When re-analyzing Zach Snyder’s Dawn of the Dead (2004) with
its socio-political backdrop firmly in the mind of its audience, the
relevance of the film’s bizarre title sequence becomes disconcertingly
clear: Snyder’s zombie is a manifestation of radical Islam.
In Western historiography, there is an established pattern of viewing
Islam and Muslim culture much as we view zombies today. This discourse
has many stages and contributors that can be traced to orientalist
writings of the early modern period. Its central claim is that
Muslims, unlike the followers of other religions, are intellectually
and spiritually deadened. The idea most clearly emerges in the
paradigm of Muslim fatalism.