Well, it is obviously a joke. Just because all the self described libertarians I know (including myself), also think that policing is an appropriate role for the state, doesn't make it a bad joke.
However, it does make it a joke that displays ignorance of what libertarians believe. Which in this forum is a relentless, sustained phenomenon.
It seems accurate to me, based on the sources available.
The problem may be that, as you've previously stated, libertarianism is a political principle, not a desired end state for society. Different libertarian thinkers have different ideas about how to embody those principles. Because of that, there isn't really a 'libertarian society', and efforts to portray such are often dismissed by libertarians as 'not libertarianism'. There is no true libertarian society just as there is no true Scotsman - any proposal will fall short of the ideal.
But politics isn't only about ideals. Anyone who regards libertarianism as more than an idle talking point has some responsibility to say what form it would take, just as those who support free speech, or torture of prisoners, or the death penalty, have to spell out how to deal with the consequences, and give some idea of how far that principle will go. And the problem with libertarianism, indeed the primary problem with libertarianism, is that any attempt to portray a society that has embraced those principles invariably leads to comedy or farce.
Which is why we have a parody in the New Yorker, an international mass-market publications with millions of readers, that tries to combine a number of Libertarian principles into a single portrayal of a society, and the result is frickin' hilarious. The principles are accurate, the society isn't one that even a Libertarian would support, and
that's the point being made. Libertarian principles don't lead to a desirable result. Which means either that the principles that Libertarians profess are wrong, or that (more likely in my opinion) that whether or not a principle is Libertarian or not is not a useful judgement as to whether to embrace it.
The article is funny because people around the world recognise the principles being parodied. It's not necessary for a Libertarian to agree with the society portrayed for it to be a sound argument against Libertarianism. All that is necessary is that Libertarianism itself provide no guiding principle to distinguish the parody society from one that Libertarians would like to see. If it doesn't, and some of your previous comments that separate libertarianism from portrayals of libertarian societies would suggest that it doesn't, then there is a problem. The problem is nothing to do with the supposed ignorance of people on this board of what you or others believe, the problem is one within Libertarianism itself, in that it doesn't distinguish between something workable, and something ridiculous. Which may well be why so many people with odd views self-identify as libertarian, and why so many libertarians are so reluctant to describe their position in anything but the vaguest terms.