For the most part, these equines do not live on private property -- they live on govt-owned land. FYI: The govt (state & federal) owns 91.9% of Nevada, and 50.2% of Arizona. The problems with non-native equines occur on govt land. I'm glad they are a part of the solution.
But if the government did nothing, I guess you guys would be raising holy hell about the donkeys and horses.
Surprisingly enough, it's typically the reverse. The locals love "their" wild burros and horses and hate to see them rounded up. But because there are numerous stories about local roundups, the local populace does seem to understand the need to cull the herds.
One last point: You would think that Westerners are the chief adopters of these equines. According to the BLM, however, more burros are adopted by residents of the Southeast than any other region. So that burro you see in a Tennessee pasture -- it probably came from the Black Mountains of Arizona.
I saw a news report recently about some “animal rights” folks whining about the roundup of the feral horses. They approved the sale of these, but were against them disposing of those not sold. Of course, they also were pleading for money to end this.
The adoption program for these is wonderful, and yes, there are many here in the southeast who buy these. We have a lot of public land here, and horseback riding in the national forest is popular.
Many of the “kill no animal” crowd (mostly urban folks with no exposure to nature except TV)do not realize these are NOT native animals. We have the same problem in a national park here with feral hog/wild boars. They destroy native fawna, including food for other wildlife, and are very destructive. Since it is not legal to hunt these in the national park, the park service quietly brings in sharpshooters to control them, and those who think hunting is “cruel” are pacified.