I'm sorry you have to deal with that. And I'm really sorry that her parents are such complete assholes. Permitting your child alcohol, once in a while, is one thing. I grew up that way, and one of the reasons I was never, and still am not, all that into alcohol is because it just wasn't that exciting when I was younger; mom and dad were okay with it, so it didn't make my teenage-rebellion sense tingle. But refusing to set limits for your child and not calling them on their shit when they've gone too far is complete and utter incompetence.
I totally agree with you. I grew up like this, too. My parents weren't blasé about drinking, because they didn't drink much and didn't want me to pick up the habit, but we had alcohol at home and letting me have some just wasn't a big deal. There was no "forbidden fruit" aspect to it, so I never felt the urge. Nowadays, I drink on average once every 3 or 4 months, and not to get drunk. Before college, I tended not to pick friends who were enamored and obsessed with alcohol because of its forbidden allure, because I thought they were idiots. I had goals to meet while they partied their lives and their grades away. I grew up raised with the sentiment that it's just a drink--no more, no less, so I exorcised my rebellious teenage tendencies elsewhere in ways that wouldn't cut off my nose to spite my face.
Now that I'm in college, I understand the urge people have here to party, to drink, because some of them work so hard that they need to let off steam, but there's a difference between responsible social drinking and consistently passing out on the street because you're always out of control when you drink.
(By the way, I saw someone recently just pass out on the sidewalk just like this two blocks away from my apartment as my roommate and I drove home from late night grocery shopping, and two of her friends let us know when we slowed down for her that we didn't need to stop, that it wasn't an emergency--"It's okay, she's just drunk, she needs to rest, we'll take her home." I mean, yay for Safeway being open 24 hrs., but man, some of the things you see late on a Wednesday night. ...I am such a cranky old woman.

)
People should have to pass a common sense test before they're allowed to procreate.

Yes. But one would also think that people would need a common sense test to actually live, and yet they bumble about still alive despite that, so... ::shrug:: It's like the people who go to zoos and purposefully and consciously ignore all the signs and the fact that there's a dangerous animal in the cage/habitat, get their arm bitten off by a tiger, and have the nerve to complain about it. Natural selection--we should let it take its course, that's all I'm sayin'. (I'm a jackass sometimes, I'm aware.) But you know, in a couple of decades, it's predicted that this planet is going to have 8 billion people on it, and part of that population will be born from people who wouldn't pass a common sense test. And that's a sad thing for everybody.