I've heard about this & don't think there's anything wrong with it. The hunting skill level involved to be successful is phenomenal & when you come right down to it.......it's the ultimate way to take game unless you're carrying only a knife or a rock.
Actually, it's a lot more "sporting" than a person sitting in a tree stand with a rifle that can hit pennies at 300 yards. And given the enormous number of injured, maimed, wasted animals (deer) left in the field/woods every year by rifle hunters that are poor shots & don't know what they're doing......the kill ratio might actually improve with a skilled hunter.
My eldest daughter has a field trip last year as part of their study on Alogonquian Indians. Part of the set up at the State park was putting stuffed animals in the field & having the kids have a go with the spears those indians hunted with. I can't remember the name of the device, but what the indians did was notch the back end of the spear & use another stick, sort of like a handle, which was also notched to give mechanical advantage in flinging the spear. Talk about tough! Sheesh, those targets were set up close & it was very, very tough to even get close to one. Made you appreciate. It was cool.