A failed attempt to target a gladiator with Hateful Whisper through darkness:

A successful attempt to target the same square with Hateful Whisper, without the darkness:

Showing that I am able to shoot through the darkness when the post isn't a consideration:

I suppose this happens because darkness is supposed to mess with targeting. But it shouldn't mess with targeting if I can see through it with my Dark Vision talent! It just makes no sense.
Another egregious example, this time targeting Agony (range 7) in a straight diagonal line through darkness:
