I know hunting is not a simply good or bad issue and involves varies other reasons which when entered into the argument can make hunting seem viable. Unfortunaley that's not the case in my country. The birds shot down do not cause harm to the environment and are not a niusence. The government even stipulates how many birds can be killed so that overall damage to the ecosystem is not done. So yes in my country ( on which the op 's opinion are based ) it is a simple Good or Bad situation.

I take it you've never owned a cat or dog. Cats are especially sadistic. They love to shred rabbits apart and play with them, often getting pleasure from their screams. Also, when people say " for fun" what is really happening is the process of learning to hunt is "fun" not actually killing the animal. That would fall under your category of "training." 

I'm for it if you actually eat what you kill.  I don't feel that strongly about it, though. I care more about human beings

I'll support the killing of animals that are consumed for food and other things to a point. If an animal species is invasive to an area and doing damage then I support the species' annilation from the area. I believe in the conservation of animals though if it's endangered or overhunted/overfished. Overfishing is more of a problem worldwide and some kind of a agreement needs to be done/enforced. 

Quail hunting is absolutely one of my favorite types of hunting. It is challenging, and they taste amazing.

As far as I know in the United States, it is not legal to hunt animals and abandom them, and you will be fined heavily if caught.  They have to be used.  It is illegal to just leave them to rot and waste.

Hmm, well, most things we find "fun" are also related to the survival of our species. That's why they are "fun" our ancestors who found these things "fun" were more likely to survive and pass their traits on.

Sports and competitive video games also trigger "fun" feelings, due to the conditions required for tribal survival, back in the day.

Cats hunt mice, and dogs chase cats, for similar reason. Also, many dogs don't take any interest in cats (like my current mutt), just like how some humans don't find sports, or videogames, or hunting, fun.