Oh, look at the cute deer...

The deer attacked because there was a predatory creature dangerously close to itself and it’s offspring. Stop trying to think like a person and start trying to think like a wild animal.

Although you could be right, maybe this deer was deliberately out to get this dog. Scoped out the neighborhood a month in advance to learn the dog’s routine and habits, learned it’s every schedule, and when it felt the time was right it just set up the perfect trap.