Hell, the black powder .45-70, used by US troops and civilians starting in the 1870s, is still used in
competition at 1000 yards. It's quite accurate, if it's loaded right.
The Billy Dixon
legend says that he knocked an Indian off his horse with a .50-70 at more than a mile. Others say 1538 yards. Later measurements by a surveyor put the real distance at a bit over 1000 yards.
So while the original story was a bit exaggerated, the truth was still impressive.
http://findarticles.com/p/articles/mi_m0BQY/is_6_51/ai_n13781619
These rifles were, obviously, primitive by modern standards. These were the working rifles of the professional buffalo hunters, with iron sights.
So a claim that a modern rifle with a high-power scope could,
theoretically, hit a person at 2000 yards, doesn't mean much. Of course it can. But how often has this been done? Every hunter knows you can miss a big deer at 50 yards with a sub-MOA rifle. And what importance does the theoretical range of the .50 BMG have in terms of public safety or military strategy?
Note that our enemies in Iraq use roadside bombs, not .50 BMG rifles. IED's are a terrorist threat many orders of magnitude greater than any rifle, both in terms of real-world fatalities we can count, and their potential.