If the boy did a flamenco dance while up there, that could cause the dog to react by biting if it's really hurt and in the process of moving to bite or even to get away, the child is going for a tumble, possibly knocking his head or face really hard.
Even if she didn't care about the dog, letting a child stand on an unpredictable and potentially moving object is really dumb. That is a tile floor and his face is over the edge of the counter.
Trig could've been hurt if the dog leg him know.
Oh and does it piss me off? Yeah, kinda though I don't care it's Palin.
I would be upset by any idiot parent who let their kid do that to the family dog, thereby putting their child in danger.