Simply by asking the question, I suspect you know what the answer ought to be.

The problem with taking it home, justifying your breach of the regulations, is that there is no way for an officer to know whether the fish was really hurting when he checks you at the dock. If it is important enough for you to take the fish home, that you are willing to accept the ticket uncomplainingly, then perhaps you did the right thing. If, on the other hand, you had been checked and ticketed, would you have been complaining here about the injustice of the ticket? If so, then you have your answer.

The enforcement folks have to force release of fish, even if mortally injured, because there is no other way to keep Gap Tooth Charlie and his friends from bonking everything they catch, claiming that it was bleeding. Sadly, if it were acceptable to allow keeping of mortally injured fish, the percent of mortally injured fish would skyrocket overnight.

If you think that it is worthwhile and good for the fishery for us to have game regulations, then it was harmful for you to keep this fish. If you think game regulations are simply obstacles to be surmounted in your quest to kill every fish that you can, well, no amount of sermonizing will convince you that there is a valid reason behind the law. I happen to think there is a reason, and a good one, for requiring that even mortally wounded unclipped fish be let go.