Being new to this fishing as well, decisions out in the water can be difficult. Do the fish have fight left after injuries, sure they do! then you get into statistics and areas that are out of our realm. You have to live with the dicisions you make, and pay the concequences wheather legal or moral. Can we change our fishing techniques, sure! But if we do that, then we will boil it down to fishing with safety pins and using the force all in an attempt to save the fish. If it was in the river, I could see letting it go, it might make it. But out in the salt water, I don't think it's gonna happen. I believe you did the right thing.
Just becuase everyone says somethings right, that don't make it right. Laws are in place for anglers that don't give a hoot. You appearantly do. It's all good in my eyes, I would have done the same thing.