A DUI doesn't hurt anybody but the driver?
No, it doesn't. Think what the crime is: Driving while intoxicated. Not "Driving while intoxicated into a busload of handicapped children and puppies" or whatever MADD is saying that all drunks do these days. No mention of hurting anyone, that would be called vehicular assault or manslaughter. Just driving. That hurts no one, the only difference is that you're in a particular mental state that makes you more dangerous behind the wheel, kinda like being female (kidding). You seem to be under the assumption that everytime someone gets behind the wheel, they kill a cute happy family of five. Patently untrue. Most drunk drivers have done it many, many times before they get in an accident.
I'm not, of course, advocating drunk driving. It's one of the stupidest, most immature things you can possibly do. I don't do it and I don't let any of my friends do it. It greatly increases your chances of getting in an accident, just like (statistically speaking) being black increases your chances of being poor, getting into the NBA, and having sickle-cell anemia. But just like we shouldn't hand out money, vaccinations, and basketballs to every black person we see, we shouldn't hand out convictions to every drunk on the road.
Since I've had problems with this before, sidenote on the above: Don't try and construe something racist out of that. I'm just using true statistics to create a humorous example of my point. My tongue is so far in my cheek I can taste my own facial hair.
Once you do hurt someone, then you've done actual tangible harm, and for that you should damn well be prosecuted. I have already said that the penalties should be much stiffer for vehicular manslaughter committed while under the influence.
Drunk driving IS wrong, but just like other things that we may or not believe are wrong, such as drug use, prostitution, etc., we should not enforce our morality by legislative fiat.