I'm pretty sure the fawn was just born not too long ago. They gain their footing pretty quickly after birth, maybe a few hours or so, but if you notice, it was flailing a bit and even fell. Either that, or it was injured. Either way, enough for Mom Deer to go into instinct overload.
But I agree. The dog, yet again, is punished for a human's mistake. Why is your dog outside unleashed anyway? And plus, that deer was hanging out for QUITE some time before it got to the dog. Maybe if you called Star inside, he/she wouldn't have gotten curbstomped.
I too, wonder what would happen if it was another, more able, dog. Something with baiting instincts.
Winner of this thread: CAT.