The CPS are the biggest problem in my opinion.
They are only interested in prosecuting people if they think it is an easy win, and the sentences handed out are often too lenient, or too far the other way.
I think people sometimes get angry with the police for not doing enough, but I can say from experience that a lot of the time they don't push for prosecution because the CPS tell them not to. It's why a lot of lower level violence and burglary etc, rarely get convictions. They just aren't interested. Then you have a cockwomble like this who gets a metaphorical slap on the wrist for taking someone's life so irresponsibly. The system is in a really bad way.