Re: smoking & drinking... Smoking tobacco, particularly, has been a public health catastrophe in terms of deaths, disability, and illness during the 20th century. Where the percentage of smoking was once not too far from 50% of adults, it is now down to around 15% of adults (in the US). As a result, lower rates of heart disease, lung cancer, and COPD are becoming normal (but not for the 15% still smoking).
Alcohol addiction has been less of a problem, but one of greater intensity (and shorter duration). Lots of people aren't here anymore because they died of alcohol related accident or disease.
I'm not quite sure what the current national stats are on drinking and alcohol related disease.
I used to smoke (24 years ago), used to drink quite a bit (still drink a little), and used to engage in unsafe sex -- which for gay guys in the 1980s was playing with fire. Why do people do these things -- drug use, smoking, drinking, unsafe sex, hang gliding, etc. that have known and fairly high risks? I don't know. I have been more risk tolerant than some people in these areas. In financial matters I'm much more risk averse. Why -- don't know.
I'm surprised that the morality of using illegal drugs has attracted so much interest. The illegality of cannabis has seemed absurd to many people for a long time. I think opiates and amphetamines are more dangerous, but I don't see them as "immoral". Snorting coke or smoking crack might not be good for a person, but if one uses them occasionally they probably aren't that harmful. (But some people seem predisposed to addiction -- then it becomes a bigger problem for the individual and society.).
Know one is HIV+ and failing to disclose the fact to unprotected sex partners is morally much more problematic than smoking weed, crack, meth, or shooting up heroin (other factors being equal).
Gay sex was unambiguously immoral for most people when I was a child. It's taken a good 60 years of concerted efforts on the part of a lot of people to move the consensus to homosexuality being neutral for most people, like it is being heterosexual. (This situation isn't fixed for all time, however. We could always see a back-rolling of progress.)
Childhood has become highly freighted over the last 100-150 years, or so. Where once children were merely miniature adults, and more or less as durable, they gradually became innocent, precious, and vulnerable to all sorts of potential harm. (Based on the testimony of numerous people in print and in conversation)... many of us who are in our 70s and older can remember a time when children were sent outside to play--whatever that might mean to the children, wherever was available. We weren't supervised, for the most part. Our being gone for two or three hours was not alarming.
Was the world perfectly safe 70 years ago? No, of course it wasn't. There were plenty of serious risks of getting hit by a car, drowning in a stream, getting poisoned by tasting fruit in the woods, getting bitten by something, falling out of trees, getting into fights, stepping on nails, and experimenting with sex. Were our parents stupid? No, they apparently accepted that children playing on their own would take risks and might get hurt. Sure, we were advised and warned, but children on their own for the afternoon forget the details of good advice.