The more educated you are on the ballistics of your rifle the better you will be as a hunter.
Meh... to a POINT perhaps. But not really.
Most big game animals are engaged at 100-200 yards. At those ranges, and even out to 250, ballistics is largely meaningless in most modern rifle cartridges. Instead, you use the concept of 'max point blank' range and forget about the ballistics.
The average hunter will be no better off knowing more about ballistics. They'd be better off studying the animals from all angles to have better knowledge about lethal zones, or to spend more time learning how to accurately guess ranges.
In addition, i believe what the poster was saying is that ballistics and energy becomes the prime focus for many newer shooters when picking a gun. And that leaves out a number of very important factors such as recoil or even cost of bullets to practice with. A guy with a 30-06 who's run 200 rounds thru his gun in practice when he got it will be more likely to hit his target than a guy who bought a 338 and can only afford to shoot 80 rounds because they cost more and they hurt his shoulder. You get the idea.
Now dont' get me wrong - if you want to know more about your guns ballistics there is nothing wrong with it. I think it's a great thing, i definately study ballistics and I also take a fair bit of time dissecting the animal to see how different cartridge and bullet combinations perform. I'm definately all for understanding the ballistics of the gun.
But for most hunters, it's really not necessary. All they need to know is that if they're 2.5 inches high at 100 they're 3 inches low at 240, so shoot for the vitals. And maybe that at 350 they can put the crosshairs on the top of the shoulder and still drop into the breadbox. They should really think a little before shooting much farther than that, the VAST majority of hunters really aren't trained for long range shooting, and you get into problems of animal tracking and recovery.
If you have a 7mm remmag, you really don't need to know very much about ballistics to hunt big game animals in north america for 999.9 percent of shots. Even more so if you have 300 winmag.