Perhaps it is time we started calling things what they are.
To take another persons life is murder (There may be extenuating circumstances but that does not change the fact that a life was taken.

To take another persons car is not joy riding it is theft at best the cars are often left burnt out or trashed becoming an eyesore. so often however the car is crashed taking innocent lives if that happens the charge should be murder.

same with drink it appears to be used as some kind of mitigation for what happened. It is not a reason if the perpetrator hadn't chosen to take that drink the person with thier head kicked in or lying dead in their car or by the side of the road would not have been put in that danger if drink is used as the excuse the sentance should be doubled.