While the outcome is a tragedy in either case, there is a significant difference in whether it was truly an accident, or if one of the parties involved in the accident willfully and knowingly significantly increased the chances of an accident by, say, being drunk or texting while driving.

As a society we realize that certain risks will always remain, and due to bad luck accidents will always happen: We accept that and live with that. What we do not accept is behavior which unnecessarily endangers a person's life. It's perfectly reasonable from a moral point of view to hold people accountable in proportion to how reckless they are acting.