Horses are only here because humans brought them here. 

The new reality is that humans and other animals now shared a human-controlled planet. If we didn't engage in some animal management to counter balance our land grabbing then we would lose far more species and have an even more unhealthy environment. 

If you have a realistic solution that would actually get enough support to work, feel free to share it. Until and unless you do, this is what we have now. We manage game and non-game species for their benefit and ours.