Yeah, easy to drive something like this to the unthinking..horses evolved as grazing, herd animals. True enough. But for as long as humans have used horses for anything other than food, they have been confined, in some way or other, out of necessity. Archeological digs have found the remains of horses chained to walls in Pompeii....I can just hear Alexander the Great saying, righto, lads, the Hittites are coming, go and catch your horses. I can see them now, tearing round a paddock in the dark to round up the war horses. Just, no. At the least they'd have been tied to picket lines or hobbled.
Any performance horse, not just a racehorse, esp in and around large cities, has to spend most of its active life stabled.
NZ is one of the few places which has the scope to allow such horses space. There are some magnificent equine establishments all over the world, but such property is not available to all. Even the French and UK/ Irish regimes, very different from here, certainly, with the scope of the training grounds, still stable their horses.