Ok im pretty sure you have very little idea what you're talking about because most of this stuff is dead wrong. The mortality rate for catch and release is around 2%, nowhere near "most of them". As for the 'trauma' of being caught, just think about it: fish get attacked by predatory fish all the time. For them, getting caught is like being chased by a predator and escaping. Its something they deal with constantly. While its true that a fish with no slime is more susceptible to disease, fish are really good at making new slime. How would a net even take the slime off anyway??? Handling the fish is what takes off the slime, but as long as your hands are wet and you keep contact to a minimum the fish will have no trouble at all replenishing that slime. Have you ever been diving? You'd notice that pretty much every animal down there, from the big ass barracudas to the little blennies has spines. Almost everything a fish eats is gonna be sharp, and a lot of those sharp things are gonna have poison/venom. Why is a hook any different from the spike covered crab that fish just ate?

To be fair, some fish species should not be targeted for catch and release, like ones that live in deep water or just aren't that hardy. The types of hooks and gear you use also make a huge difference. An environmentally conscious fisherman doing catch and release with the right gear and knowledge is not cruel.

Sources:Been freediving, spearfishing, and regular fishing for my whole life and http://www.acuteangling.com/Reference/C&RMortality.html for the statistic