Not everyone can bench press 500 lbs, and is made of iron...Although, I'm betting that if you were to shoot that rifle from prone or from the bench 50 times in a practice session (the average guy zeros and practices from the bench, remember), you'd see your first bruise.
Everyone I've known who has used them (or the Past brand ones) says that they work way better than they ever would have thought possible. Everyone. There's no such thing as bad recoil, just bad gear.
I'm glad you make sure to use effective gear to mitigate recoil-related shooting issues. I've got a fair bit of experience with Past recoil shields, muzzle brakes, bench-mounted vises, etc, but of course the majority of hunters don't use any form of artificial recoil reducer. My previous comments about my observations were in reference to mostly average hunters that simply shoot their rifles. And without the Cabelas pad, a muzzle brake, bench vise, etc, assuming a sporter-weight rifle, I'd probably win the bet about the bruising. Either way, the effect I described is real, and while it can be mitigated with effective choice of equipment, most people are either unaware of those options or just choose not to use them. There's nothing wrong with using magnum rifles if you can manage the recoil and muzzle blast without developing an aversion to firing the rifle, but lots of people that I've observed shooting magnum rifles simply can't/don't manage it well.
In terms of factors that affect "killing power", I think most serious hunters would agree that between shot placement, bullet construction, and caliber/bullet weight/velocity, the ranking would be placement first, then bullet construction, then caliber/weight/velocity. Ideally, maximizing all three factors would produce the most "killing power", but in the real world there are trade-offs. Even if a person can handle shooting magnum rifles, it's more enjoyable for most people to shoot a rifle with less blast, recoil, and ammunition cost, so people tend to practice in higher volumes with smaller rifles, and as a result they tend to shoot better and have more confidence in their rifle when using a smaller cartridge. This especially holds true for the average hunter that doesn't invest in becoming proficient with magnum rifles. So when I say that I've seen more people lose critters by being over-gunned than under-gunned, it's because they traded the most important factor (precision in shot placement) for the least important of the three factors ("rifle power").
Either way, the effect I described is real, and while it can be mitigated with effective choice of equipment, most people are either unaware of those options or just choose not to use them. There's nothing wrong with using magnum rifles if you can manage the recoil and muzzle blast without developing an aversion to firing the rifle, but lots of people that I've observed shooting magnum rifles simply can't/don't manage it well. 
