So many Americans are alcoholics. It's not just "girls" but people in general.
I know of a dozen in my circle alone. A couple don't realize it yet, a couple I've made mention to but are still in denial, a couple actively seeking help, etc..
IMO, it has everything to do with American drinking culture, which socially pressures people to drink at almost every social gathering. There are entire social events centered around drinking, and almost nothing else. (for example, pub crawls)
Now that I'm a family man, and don't have the time for all of that shit anymore, I now see the type of people who I was surrounded by. You have the standard, easy to spot, day drinkers who always smell like alcohol... even sometimes at work. You have the weekend binge drinkers, who almost always eventually start spilling that over into the business week. You have the more subtle "hide my alcohol in a coffee cup" types who are in complete denial about what they're doing, and tend to blindside you when they get slapped with a DUI or hurt themselves in some other alcohol-related way.
You have the perpetually tipsy "wine moms" who I didn't realize were a thing until I got a family and am now exposed to them on a weekly basis. I see them among quite a few soccer mom-types. They all, to a woman, have this warped belief among them that they are owed their wine due to raising children and/or just love the idea of the "classy" glass of wine that what initially started as vanity, eventually turns to habit, which eventually turns to excess, and so on. And no, I'm not picking on the women, because I've seen that men have their own version of this.