I tend to think the particular brand of pearl-clutching teetotal types must've either grown up in homes where alcohol was abused (in which case their stance is completely understandable), or in temperant homes and think of it as some sort of evil, and are genuinely scared of it.
Vast swathes of people (I suspect the majority) come from homes were alcohol is/was consumed, and everyone went on to lead perfectly normal, healthy, loving, functioning lives.
We see the bad news stories and evidence of people abusing alcohol, and forget that this is not most people. Not most adults.
Both my parents drank alcohol (to be fair, DM very little), but I never saw them drunk. They entertained a lot, and I don't remember ever seeing any of our family friends drunk either. That was my model, and I suspect it's many other people's model.
We entertain a lot, too. Alcohol is pretty much always involved, too. Everyone has a great time, lots of laughs, and then goes home. I am certain this is not unusual, because whenever I go to anyone else's house, that's what happens to.
Do people get rip roaringly drunk? Well, yes, sometimes, but that's the exception (and obviously not when DC are around). We all have kids we have to get up with the next morning and/or jobs to go to.
We're adults that enjoy a good time, and are mature enough to know when we've had enough. This is the norm, I am certain of it.
It's just people who haven't grown up around this that can't understand it.