And in some cases I disagree with that because I tend to err on the side of personal responsibility rather than society having to follow you around and make sure you don't screw up.
But it's at least a bit more justifiable -- the bartender can usually see, right now, that the guy is falling down drunk and shouldn't drink any more. And I said usually because I used to work with a guy who'd be about 23 sheets to the wind, but could, on command, act and speak as though he were completely sober, for a short time anyway. It was actually amazing how he could do that - he could easily fool a bartender if he wanted to.
And really those laws are either lax or loosely-enforced because I've been in a lot of restaurants and bars and watched a lot of people who are absolutely bombed out of their gourd and can still get more booze. More often I see that being used when the customer is obnoxiously rude to the bartender as a way to get back at the customer.
Taking someone's car away for lending it to someone who then drove drunk... There's just no way to guarantee that the lender knew the guy was going to go get drunk.
Those two concepts aren't mutually exclusive. Lots of people drink once a week or more, and don't have drinking problems. I'm personally not going to assume that someone who has a few beers on Saturday night is an alcoholic who drives drunk.