I am probably going to piss someone off saying this but here goes anyway, because people are stupid, arrogant, and in some (possibly a lot) completely uninformed. A lot of hunters hear something somewhere or read some article by one of the dipshit talking heads being paid by ammunition companies and take it as gospel.
Don't get me wrong, you don't have to be a certified ballistics expert to hunt but like anything else in life you get out of it what you put into it.
Additionally, its for the same reason that the majority of hunters shoot their rifles once to sight it in, once before season if you are lucky or in the case of a guided hunt the outfitter requires them to check zero before a hunt, then once at an animal if given the opportunity. So at best they shoot their rifle 3x a year. In my experience with clients over the years those shooting things like Core-Lok's almost always fall into that category.
We try to educate clients when the opportunity arises and in a heck of a lot of cases it is because the client is brand new into hunting and just doesn't know. The rest, a much smaller portion are just plain cheap or don't care.
This also leads into another soap box rant on people shooting way too much gun for their skill and ability level. When the guys show up with a 7000 Weatherby Ultra Super Magnum to hunt whitetail and talk about how they can shoot the eye out of the gnat at a million yards with their shoulder mounted artillery piece its hard not to roll your eyes because you know its going to be a hellava long few days. In 100 % of the cases with this I watch them then cuss that same gun or the scope for being off and something "changing" while verifying zero at the range and they cannot even hit a lifesize metal deer target we have set up at 200 yards anywhere on the target neither off a bench or sticks. The fact is you can watch them flinch so damn bad they about jump out of their shoes because they are scared to death of the recoil that's about to happen. This is not to say that there are not people that can shoot those big mid-bore belted magnums proficiently, sometimes barring on exceptionally. There are, but they are certainly the exception not the rule.
In both cases I think the majority of the time its a combination of machismo and ignorance. Men tend to think bigger is always better and they "know what they are doing" when quite frankly those types wouldn't know their elbow from their asshole. I hate to say it but it is really an issue with older people, my age and up. The younger group of hunters, women, or hunters that are older but are late bloomers in their hunting and shooting careers (for lack of a better term) are generally squared away. They show up with some pretty impressive custom rifles, most of the time with their own hand loads or premium factory ammo. That group of folks are some shooters.
Now there is one person that I have had the good privilege of hunting with that fits neither mold and that is our own AH'r
@Hogpatrol. He's an old fart
but, that dude I am pretty sure could literally shoot the wings off a fly with just about anything at any range. He is definitely in the top 3 best shooters I've ever been around and knows his shit. Point being, before I get blasted for what i have said, there are exceptions to every rule. Another guy i have hunted with who due to his work i will not say his name is indeed a younger guy, in his late 30's, who didn't start shooting until he was in his early 30's but has spent a hellava lot of money on shooting courses and shoots several hundred rifle rounds out of each of his main hunting rifles a month. He is probably one of the most dedicated rifle shooters I know and sheesh that guy can shoot. He struggles a little on animals as he gets pretty amp'd up (really not so much anymore now) but good lord I've seen him do some very very impressive shooting and he's won idk how many long distance competitions over the last few years.
Sorry for the rant but hey the question was asked.