The king, you described my grandfather. Was fishing here at turn of the 1900's with cane rods (baitcasting and fly). I still have a steel and bamboo fly rod of his, and his old split bamboo baitcaster. BUT, back then they would drag the fish on the bank/gaff and dispatch ASAP. But, back then you didn't have alot of people fishing. I heard stories of my granddad fishing all by himself on the Puyallup (this was about 1912 or so on his visits to my Uncle at Camp Murray). So, you HAD to land by yourself.
Myself, I want that fish caught and release with as little harm as possible. Especially in a boat. Safer on the fish if you have a netter to quickly scoop fish up. Tailing a king like that isn't an option (unless you have monster hands like me, and STILL is a problem). I grew up with strict fishing ethics as well. But, more stress at banging fish on head by accident selfnetting. Or damaging rod doing this (have seen that a few times out in the sound). Also, back in the "day", they would also gaff the salmon. My Dad still has my Grandpa's and Great Uncles salmon gaffs (since very rarely were ANY fish released back in those days, even by flyfisherman).
I feel, go with whatever you feel. Neither is wrong or right. Would be like saying, who's the better fisherman, a fly angler or a gear angler? It's all on your perception. Playing a fish out over and over again trying to net it isn't as sporting as a quick scoop/release by another person. That's MY perception. So, we all have difference of opinions. But, was an excellent catch. No complaints by me. My biggest weighed was 58#'s. But had one that I know was bigger, but didn't tape it. Was king release, so simply put back into the water.