But... didn't horses originally evolve in the Americas? Not to start an argument over semantics here, but I think the fact that horses so quickly got a foothold in the ecosystem when they were reintroduced means that they shouldn't really have died out or whatever in the first place. We went over this briefly in one of my classes last quarter. The horses in the Americas were probably killed off by early man when he got here over the Bering Strait; they probably didn't go extinct due to natural causes. Even though they're technically an introduced species now, it's reintroduced. I don't really think they count as an invasive species.
I don't really know too much about the modern roundups, but I think it's funny that this article is coming out now because I just started reading a biography of Wild Horse Annie (AKA Velma Johnston) a few days ago.
I think the roundups are the best of however-many evils. It's better than letting random citizens go out and poison their watering holes, which apparently used to happen. They also used to let whoever wanted to round them up do it. Untrained, uncaring, they could do whatever they wanted with the mustangs. And at least now the government tries to sell some--or most, I don't really know--of them, instead of packing them all into trucks to transport to wherever to be slaughtered. Maybe there are better ways to do it, and maybe someday someone will come up with a feasible solution, but for now I don't think there are any good ones that are also workable on as large of a scale as the government needs.