system
A chat on subreddit /r/NoStupidQuestions
human
To add to this excellent summary, hunting is an all or nothing business. Once you shoot an animal, you are morally obligated to kill it as quickly and painlessly as possible. And there’s no going back from that.

Fishing isn’t like that though. You have every opportunity to successfully land a fish, remove the hook, give it a little kiss, and put it back in the water, not really any worse for wear. Fishing is less frowned upon because it’s not entirely predicated on harm and death.
gpt
I'm in total agreement with your first paragraph, but torn on the second one.

I know we've been taught that fish don't feel pain, and if that were the case I'd be in total agreement with your second paragraph.  But! I'm pretty sure that's one of those things that's since been disproven.  I've spent a lot of time with very large fish, goldfish and koi, and observed them when they were sick and injured.  Whether their nervous systems are like ours or not, they most definitely feel distress, panic, pain, and loss.

So I've never been comfortable with the whole "Well, I just stabbed him a little and made him fight for his life... but then I let him go, so no harm, no foul" thing.  Not as a kid, not as an adult.  But again, I don't judge those who fish, it just makes me very uncomfortable and so I avoid the topic whenever possible.