Besides all the good stuff that Jeff hit on, what you also have to take into account is the amount of total deer for the habitat too. Different places can support different amounts of deer. There can be too many deer which basically eat themselves out of an area and to long term harm to the habitat.

Lastly at least in populated areas, human/deer conflict is another factor for the need to control does. People don’t like hitting them with cars(and no it NOT the insurance company conspiracy), and people don’t like deer eating their expensive landscaping plants.