Whether or not you or any other citizen believes it was involuntary or not isn't applicable.
The verdict was read a while ago. They already told you he was getting off lightly. Now people are surprised that he actually did get off lightly.
You can form your own opinion all you want, but fortunately the court and the system doesn't care what you think.
What did you expect? A 15 year sentence for involuntary man slaughter? It went down in the books as an accident. The game was over a long time ago.