To me it's clear that deer are both sentient and intelligent. As an easy example, I frequently see them reacting to my dogs. When the dogs are inside the fence, the deer look at them as if they were saying "Bark all you want; that fence won't let you do anything I care about." When we're outside the fence, although the dogs are leashed, the same deer react very differently. A large canine not contained by a fence is an occasion to depart the premises post haste. On pure instinct they'd run in either case.
It's also becoming apparent that in pressured areas, they're starting to look for trouble from above, even in areas where there haven't been any cougars/pumas/panthers/mountain lions for decades. That suggests that they are learning the role of tree stands in their lives.
To me, that doesn't mean that they should not be hunted as food. In the final sense, we're all food for something. Our own reign at the top of the food chain is also temporary. At some point we die and the remains become food, if only for bacteria and microbes. Nobody stays at the top of the food chain forever.
The fact that they are sentient and intelligent, and downright tasty, means to me that we have an obligation to hunt them ethically and respectfully, to kill as cleanly as we can, to practice shooting diligently to assure that outcome and to take the food they provide respectfully and gratefully. We are all part of the great circle of life and should try, knowing that none of us will ever be perfect, to conduct ourselves with respect to other life forms accordingly.