Keep some fish for dinner, but don’t be a fish hog. IOW, limit your kill, don’t kill your limit.
The vast majority of high lakes do not have native fish. That means the biological reasons for catch and release don’t apply. Where there are naturally reproducing fish they almost always over-reproduce. You get a lake full of small, skinny fish. In that situation you are doing the lake a favor by keeping as many fish as possible.
So the only reason to not kill fish, and it is a good reason, is to save them for the next angler. In certain small lakes there might be only twenty or fifty fish stocked. It doesn’t take too many fish hogs to completely wipe out a lake like that. Most high lakes are not very productive so it takes a long time to grow a large fish. By letting them go you give them a chance to grow large.
So it is fine to kill the occasional high lake fish, but save some for the next person.
If they’re small, say 10″ or less and there’s a bunch, keep and eat as many as you can. If they’re decent size and there’s not many, let them go so they’ll grow bigger. I caught a 29″ CT in a lake at 5000′ in ONP and even though we were out of food I let it go. I hope to catch it next summer as a 32″er.