I don't get it. I dl'ed the series, and it showed black blood. I just don't see how less 'shocking' it would seem if you change something from red to black. It's still a gory scene (and the best one in the series, though that's mainly because the rest is so shitty)
It's like the censors were thinking 'ohmagawd people will freak out when they see red blood, let's colour it black and all is well'.
At least, that seems to have been their second thought. The first one being that Nice Boat.