Deer numbers need to be culled so as to make the population stable and to maintain food stocks in the area for the deer and other herbivores to eat without all of it being eaten and the animals starving to death. Deer also have an impact on their surrounding when there's too many of them, such as forestry, as they have a tendency to ruin entire forests by stripping the bark with their antlers and by doing so killing the trees.
I believe that there are already hunters out there taking deer out of the population. In some areas, there are also natural predators. I don't feel that it is necessary for state or government officials to kill deer simply because there are too many. The deer wouldn't be as problematic to people if they had more space to live.