That's interesting.The difference is how easy and impersonal a firearm can make it. Having had to finish off a badly shot fox cub with a knife is something that has stayed with me ever since while shooting foxes doesn't bother me in the slightest.
It makes no difference to me emotionally how I kill something, provided that it's done as efficiently as I can with what I've got to hand under the circumstances.
In the situation you describe, I would have been emotionally affected by the poor shooting (because that caused the suffering) but not the finishing off with a knife, because that was act of mercy. And there's been plenty of times I've killed large animals with just a knife, no firearm being handy.
