I think your previous posts have been explaining why things are not always black and white in the justice system. I was trying to expand on that and focus on the disconnect between the behaviour of the killer (not just the fatal blow) and the sentence (i.e. the reduced charge), as I think a lot of people are upset between the lack of a direct link between the two.
There will always be bad decisions made during the process as those involved are human and humans make mistakes. There will also always be those who think a conviction or acquittal is wrong, a sentence too short or too long - after all it's also human nature that we view things differently to one another and have differing opinions.
Taking all that into account, our justice system is one of the oldest in the world still being used and because of that, I think it's evolved. It's not simple, it's not straightforward, but deciding a person's guilt or innocence and the fate of the rest of their lives (along with the impact on their family, the victim and the victim's family) shouldn't be simple and straightforward.