Seems we are just simply on different levels with this discussion. That's fine, we can't all agree.
My justifications for hunting anything are pretty clear, because I enjoy it. I'll not use any smoke and mirrors to try to make it any more morally acceptable. I hunt because I enjoy it, if I can eat what I kill I will, if it's a pest I'll assist the farmer how I can. But essentially, if I want to hunt a testing beast in a sporting manor and it's not endagering populations etc then I will for no other reason than I enjoy to hunt. So there is my justification. Similar I think to the justification to fish......
Next, a fox or whatever (depending on national laws) being dug with the use of a single terrier (depending on the style of the terrier and the attitude of the quarry) will be quite alright and healthy albeit a bit pissed perhaps. At least the fox will be bouncing with energy and bound off and pace afterwards, most decent fish require a good few minutes of recovery after their experience, often carrying the wounds for it. I really see no difference between say carp fishing and digging in terms of ethics. You're catching a wild animal and releasing it purely for your pleasure....... I'm not going to condemn one and not the other.
People hunt for sport, yet adamantly claim that they're doing it for 'pest control' or to 'fill the freezer'. Yeah alright, whatever helps them sleep at night.