It's in the mind set. Many people learned to fish years ago and view fish only as food. Unfortunately many of them will never change their outlook. They are diehard meat fisherman. I've known a few. I fished with one man who got frustrated because he could caught massive pike that over the slot limit in Canada. At that time in that region of Canada one couldn’t keep fish over or under the slot limit. So 40 inch plus pike had to go back in and believe it or not he wanted to catch smaller pike so he could keep them.