To be fair, I would say that for the vast majority of members on this forum, packing/hunting is as close as they're realistically going to get to a duty/tactical/fighting type of situation. Honestly, for those who DO find themselves in those types of situations, they seldom have much choice in the hardware that is issued to them.
I mean, are there forum members that carry 15+ pound rigs around the mountains? Sure... but if I had to guess, I'd say that most folks here carry their rifles less than 100 yards from the truck/4 wheeler on average; I can't blame 'em, I do the same thing. However, for those situations where that's not possible, then I tend to fall into the "lighter is better" mentality. A shooter worn out from carrying a heavy gun is very probably going to be less accurate shooting that heavy gun than would be a shooter carrying/shooting a lighter gun due to the difference in physical fatigue. Keep in mind, too, that these sorts of situations tend to put more emphasis on first round/cold bore hits than on putting five rounds through the same hole. Live targets (whether they be game animals or two-legged critters) tend to move when a shot is fired, so it's not like the shooter is going to be likely to be presented with the exact same shot multiple times.