Bruce,
I don't think most of us, myself in particular, have any problem with keeping a wild fish, be it large, medium, or small, from a truly healthy population. Genetically, bigger isn't necessarily any better in the breeding population, altho it does carry certain advantages - large and respawning females carry more eggs than small or first time spawners. Population diversity and overall abundance are probably the most critical attributes of a wild fish population. So a lot of fish, of all sizes, of many ages, returning over the greatest period of time, consistent with the environment, will provide the greatest assurance of sustaining itself in healthy abundance over time.
Arguably, there are no wild steelhead populations left in Washington state that can support a significant harvest. WDFW maintains that some of the Peninsula rivers can, but they are disputed by some fairly well qualified counter-arguments. The science pretty well supports that most hatchery steelhead do not reproduce very successfully in the natural environment. Given those conditions, most of us have decided not to deliberately kill wild steelhead any more, regardless of size.
[Editorial begins here]
In my opinion, most of the fussing about big fish is an ego thing. And that's OK; I'm just suggesting we acknowledge our obsessions and bragging rights for what they are. Many steelheaders obsess about catching a 20 pound fish (and wild fish are more likely to attain that size than hatchery fish for some simple reasons). To fullfil the obsession, they fish the Thompson, Kispiox, Skagit, or Hoh, or someplace known for large fish. Consider this: wouldn't I accomplish a greater feat catching a 20 pound steelhead where the average is 6 or 8 pounds, compared to catching that 20 pound animal where the average size is 14 or 16 pounds? I know, you didn't ask; just a little food for thought.
Sincerely,
Salmo g.