Well, you dont' actually see him kill any of the kids--and he's already admitted to killing women and children tuskens in the last movie. The other version of this shot I've heard is different only in that when he enters, you only see him from behind, and the younglings are looking up at him, one smiles and says "Hi, Ani."

And then he flicks his lightsaber on.

And then the door shuts and they cut to the next scene of Obi Wan chasing after General Greivous.

I don't think this scene is going to see the cutting room. It's a perfect transition scene to the next sequence--and it's nowhere near as horrific as watching him essentially trying to kill his own wife and unborn children on Mustafar, even if he doesn't even really realize that's what he's doing.