(possible) major flaw

First of all: I'm not trying to bash the movie, i like it. It's just sth that bothered me. (maybe there's an explanation in the comics, if that's the case I'd love to hear it)
And it's only a flaw if it was intentional.


At the very end, after Eben smashed in Marlow's head and is reunited with Stella you see people emerging from, well, I dunno where exactly, maybe the surrounding buildings.
But it's not just any people, it's only children or maybe teenagers.

If that was actually intentional I absolutely dig the idea AND the subtlety of the presentation.
Of course: Why would the vampires extinct their food source? That would be highly counterproductive.
Therefore they kill all the adults off, have a little feast and leave the children to breed. (I mean, the vamps are supposedly quite old, intending to get older and there's not that many human settlers that hang around an area where there are prolonged nights[and pipelines])
And I think especially children would have a hard time surviving this mess.

BUT: there's two things that contradict this strategy.

first: Marlow says that they intent to keep up the Masquerade and therefore have to kill any witnesses. Purposely letting the children live to prepare themselves their whole to hunt down vampires? na ah!

second: covering their tracks by setting the whole town on fire might endager all the left behind children.



The two arguments are quite strong to support the idea, that the filmmakers didn't intent to put that notion into people's heads.

But it's still there. Why only children?

So, please, what is your take on this ?
Can it be only a coincidence that the remaining survivors are all children?(except our leftover maincharacters)

Or is this an intentional clue on how the vampires operate?