Your argument is that trout are mortal and die by other causes, so who cares that C&R in the summer months is ineffective on many lowland/basin lakes? In my opinion, anglers should be concerned with the survivability of the fish they're releasing...or else C&R is a total joke. Actually, it's worse than that because it's wasteful- at least a bait fisherman eats his catch and is compelled to stop fishing by law when he reaches his limit (even if he C&R'd the fish).
As far as Kokanee are concerned, people pretty much only fish them to eat. In that case, no sin there: "Go deep and eat!" And keep posting them tactics!