Express Sights:
More magazine writer blather. I highly doubt the much admired author of that "load of cow manure" has ever really tried distance with properly regulated Express Sights.
Absolutely you have to have a reasonable estimate of the range, and you have to be proficient with iron sights; something likely sadly lacking in other than the "keyboard sniper's" background I recon.

NOW: That said, one does see the vintage rifles with that parade of Express Sight folding leaves (often to 500 yards, sometimes with an added ladder sight to 800-1000 yards) that were apparently more common in old South Africa..
I have read, and cannot find the source right now, that those distances were for alternately:
1) Potshots at unfriendly natives/foriegners before they got too close
-or-
2) Banging away at a herd where if you bagged one it was great, and if not and one was "walking wounded" and got away……well you just went after another. Hunting ethics were not so finely developed back then.

That said, I find my 6.5x54 1903 Jeffery MS to be nicely sighted out to 600 yards with the folding leaves. You can (mostly) keep it on a 5 gallon bucket from a decent field rest position. Would I shoot at game? No. Could I keep unfriendly heads down? Absolutely.
- Mike