It's not a high horse, so much as it's an avoidable problem. $59B/year in the US is spent on alcohol-related crashes. (Just crashes, not the insane amount of crime that's alcohol-related.)
There's a death every 51 minutes from it. 31% of traffic-related deaths.
17% of children under 14 who die in a car crash involving an alcohol-impaired driver. Over half of those are in the vehicle driven by the drunk driver. That's utter insanity, and I wonder how many of those people were close to the limit and something you'd deem just fine.
I'm not naive enough to think everyone at the restaurant took Uber or have a designated driver, but I trust you're also not naive enough to think that it's not a serious problem, and it's one that, more often as not, kills innocents.
The problem is that people can get away with it, and largely do. (As you allude to.)
Please don't pretend it's a small problem, and that discussing whether longer/harsher/different sentences would motivate more people to take Uber or get a designated driver is the problem. That's as counterproductive as adopting a smug tone when discussing policy.
Edit:
> I suppose at some point you can create such massive penalties for every possible misdeed that people become too terrified to leave their homes, but I don't want to live in that world.
Enough with the straw man, BTW. I'm pretty Libertarian. But the moment you demonstrate that you can't safely manage the responsibility of driving, then I'm all in favor of strongly limiting your ability to do others harm. It's the height of American selfishness to think that the current system is sufficient relative to the problem that exists.