For good or for ill, human habitation and influence throws some natural populations out of whack. Deer in the North Central US being one example. People have depopulated the natural controls on them. They've occupied much of the natural territory over which they would roam. Humans are not amenable to large scale reintroduction of their natural predators and oftentimes such reintroductions simply don't work because of the pervasiveness of the influences of human settlement. That leaves dangerous and unstably large populations of deer. The thing that keeps those herds at a (somewhat) healthy population is the selling of hunting licenses. In the absence of human hunters willing to buy permits to cull them out the government needs to either sell more licenses to the remaining hunters or failing that, pay somebody to go out and cull the herds on the government clock. Now, all of these solutions get the job done, but recreational shooting is probably the best all around. It fills the public coffers instead of taxing them and it trains a subsection of the population to care about animals at least enough to not want them to go extinct. Hunters are generally some of the people most active in the cause of wildlife and natural habitat preservation. Barbaric indeed. Now hunting rare or underpopulated species for thrills is indeed something different. That's being part of the problem, unlike this, which is part of long term management.
