There's absolutely no better way to practice shooting deer than by shooting deer.

IMO when opportunity knocks, by all means open the door. The best point I can make is that we all hunt for different reasons and we all shoot or don't shoot for different reasons. Me, I like to shoot deer, and then I eat them. It doesn't matter where they are as long as they're mature and legal.

The thing I applaud in this instance is that the OP stood up for his principles and his intrinsic ethics to make a decision. He may not see a buck that nice for the rest of the season, or maybe even the rest of his life, but he made a tough ethical decision and stuck with it.