Wow, tough crowd! LOL
It has everything to do with handling recoil! Recoil management is just as important in hunting and LR shooting as it is in competition. The problem is that with small bore chamberings the shooter gets away with having sloppy technique. Poor recoil management isn't as much of an issue with a low recoil round as it will be with a larger caliber or lighter rifle. That's why you'll see excellent target shooters who struggle to shoot as well with a larger gun; I see it all the time. They have the basics down but get beat up when they try to apply them to a 12# 300 Win Mag. Then they go back to shooting what they handle best and you end up with the folks who believe that the small cases are the best thing ever since they shoot them so much better. That doesn't make the 6 or 6.5 Creedmoor (or any of the ballistically similar chamberings) better or worse, it just makes them easier for people to shoot well.
And just so nobody thinks I'm taking cheap shots at PRS (even though I am) I've been the RO at a few local matches and even shot a few of them with a 19" specialty pistol in 260 REM, and held my own against the rifles. That said, I'm just going to leave this here...........