I think the difference is really whether or not you have to deal with it. If people want to make godawful decisions (and doing hard drugs, no matter what anyone tells me, is not something I will ever think is a good choice, ditto to unprotected sex with strangers), then that's their call. But the problem with bad decisions of that level is that in reality, when things go wrong, it's not the sort of wrong that they're capable of handling themselves, and then you start impressing the consequences of your bad decisions on other people. (Drug addiction, alcoholism, and diseases like AIDS? Totally influence the people around you.) And children of addicts and alcoholics are pretty much hardwired to hate bad decisions like that, because they can't help but weigh whether or not they'll be the one dealing with the consequences, so. I don't have a problem with social drinking (I do it, occasionally) or that sort of thing, but. People have the right to do what they want; we have the right to want nothing to do with their risky decisions.