Hunting is entirely different from competition. In NRA or CMP Highpower competition, your target is a perfectly round black circle on a white background. The front sight post (usually) is the same apparent width as the black circle, and is sprayed with carbon black to eliminate the effects of sun angle. The rear sight is an aperture. The target (10 ring) is 6" wide at 200 yards (the black circle, the nine ring) is 13" wide). If you shoot bolt rifle instead of an AR, both the front and rear sights are adjustable apertures.
In hunting, "iron sights" mostly refers to open rear sights and a bead front. The front bead is bright, and often rounded. It's easy to make elevation errors by not putting the bead down in the rear sight the same way, or errors from how the sun shines on the front bead. The target is not a nice black circle and the aiming point is somewhat conceptual. The target is moving and, in case of a charge, is at least 6" in diameter at a range of 25 yards--or less.
In hunting, the issue is usually speed, not accuracy. Those who think iron sights are not good because they can't shoot small groups off the bench are deluding themselves.
Incidentally, I have shot 1" 5-shot groups off the bench at 200 yards with an iron-sighted AR15. But offhand, with a hunting rifle and open sights, 6" at 100 yards is more tha norm.
