It's a decent question. Not really deserving of a durr hurr really.
Probably because the point isn't to sexualize her, as it is in KnJ and most other fanservicey shows.
Or maybe it is, but the show puts on the face of a more serious anime, and sneaks in loli fanservice when they think the censors aren't looking. Airing time / channel might also be a factor, though I'm not sure when/where this airs.
Lots of possible reasons.