Hello, Internet, it's Megan McArdle again, with a friendly message about morality: You shouldn't look at stolen nude photographs of celebrities.

Yes, yes, I know — it's not like your self-restraint will prevent millions of other people from gawking. But the people in the photographs didn't take them for public consumption, and they're very upset that you're looking, and you shouldn't do things that would make people upset if they knew. There are plenty of other nude photographs out there on the Internet, taken of people who were actually willing to have you gape at them in the buff. The right thing to do is to go stare at them instead.

And hello there, celebrities: If you really, really don't want millions of strangers to see pictures of you in the altogether, then you should probably not take such photographs on electronic devices that are connected to the Internet. There are a lot of jerks out there, and there's a high risk that some of them are going to steal your photographs and share them with millions of rubberneckers.

Am I blaming the victim? Nope. People shouldn't steal your private photos! Other people shouldn't look at them! Also, people shouldn't steal cars or mug strangers or be serial killers. But there are many dedicated jerks out there in this great, big world of ours, and you have to take steps that will reduce your vulnerability to those people. Not because we should have to, but because we do have to.

The feminists who get angry when people point out the obvious risks of taking nude selfies on your phone or getting extremely intoxicated at a big party full of adolescent guys seem to be arguing that if the patriarchy went away, guys could all be culturally conditioned not to steal nude photographs or rape people, with the few sociopaths restrained by the much harsher penalties that would presumably be enacted once we end "rape culture" — that there is some way, in other words, to make it perfectly safe for young women to get trashed at frat parties or take all the nude selfies their phones can hold.

Perhaps the women's studies classes that engender these beliefs should spend a little less time assigning "Backlash" and "The Second Sex" and a little more time reading true-crime books. Because if you read those sorts of books (and I freely confess to a lowbrow taste for them), you cannot possibly subscribe to the idea that only social sanctions, well-designed law-enforcement penalties and a more equitable welfare policy stand between us and a nearly-crime-free utopia.

Take middle-class guys who kill their wives. In the annals of spousal killings, there are many stories of men whom law enforcement suspected — but didn't arrest. These include stories of men whose wives had an unfortunate habit of dying the same way, with large life-insurance policies taken out on them. Everyone was pretty sure that they'd done it — but not sure enough to prove it in court. Eventually, one too many wives dies, and law enforcement gets them. Yet it is a statistical certainty that there are men out there right now who have killed their wives and gotten away with it, despite the best efforts of the police.

I'm not saying this happens all the time, but it's not exactly infrequent. Do they kill their wives because American culture says it's OK to kill your spouse for standing between you and your new honey and/or a hefty life-insurance payout? Hardly. Is it because law enforcement frequently lets wife killers off with a slap on the wrist? Don't be absurd. Maybe there is some society where wife killing is laughed off with a rueful "boys will be boys," but we are not living there. Law enforcement takes spousal murder very seriously indeed — so seriously that if your spouse is killed by anyone, you can expect to spend quite a bit of time as the primary suspect.

When people complain that we're not arresting and convicting enough rapists, they seem curiously unaware about cases like these: cases in which there is no question that the police care and, practically speaking, not all that much question about guilt ... and yet just enough lingering doubt to make a conviction unlikely. But if you read about other, even worse offenses, the assumption that we could get rid of the crime — or at least punish it! — by putting more cultural and legal pressure on the perpetrators seems hopelessly naive.

Spousal murder persists even though it's relatively easy to identify and catch; rape, on the other hand, is inherently one of the hardest crimes to prosecute, because there are usually only two witnesses, one of whom will deny it, and the victim might have been too intoxicated to provide reliable testimony. We've probably gotten better at preventing spousal murder over the last 50 or 100 years, but not because we've educated men to understand that they shouldn't kill their wives. Rather, it's a combination of prevention (easier divorce and much more stringent poison control) and advanced forensics, which make it quite hard to get away with murdering a family member.

But I digress. The point is that crime still happens even when everyone agrees that it is wrong, and crime still goes unpunished even when we would very much like to punish it. Let's just say that a troublesome minority of people will ignore basic decency and morality and do terrible, wrong things to get what they want.

I'm not saying that culture doesn't matter on the margin. Drunk girls were probably more vulnerable to rape in a culture that said "nice girls" don't drink, and if they did, they were asking for it, so it was only natural for boys to take advantage of their condition.

Someone who's been sitting around with other guys telling each other that it's OK to steal Jennifer Lawrence's nude selfies because she's a public figure and she shouldn't take those kinds of pictures if she doesn't want them out there is more likely to go ahead and do it than a guy whose peer group says that such a theft would be gross and wrong.

But there's only so far culture can go. Criminals don't steal because they think theft is OK; I'm told they get quite indignant if someone steals from them. Penny-stock con men are not one good ethics class short of a regular sales job. Serial killers did not miss the memo on how killing is wrong. Some people do things that they know are evil because they want to, and they think they can get away with it. It is not "victim blaming" to urge their targets to protect themselves from that threat.

Of course, we should all work toward a world with less crime of all sorts. But we will not hasten that day by pretending that we're already there.

Megan McArdle is a Bloomberg View columnist who writes on economics, business and public policy.