... because all I saw was dark shapes on an almost equally dark background. There was a bump which might be a nipple, it might be a mole. And that was after zooming all the way into the picture until pixels started showing up. And since there's no depth shown, what makes you think they are actually in the middle of coitus? She might be on the side of the bed ready to get into the bed.
Y'all seem to have zero problems with cartoon mayhem and violence, but the instant a nipple (or silhouette of one)appears it's Burning Hate? Methinks your 'am i offended' meters need some re-calibration.
(Me? I see a pair of nipples every morning when I look in the mirror. Life is a little too short to be offended by body parts, or the act of two people who love each other sharing their affection.)