Not only that, but it's attempt at humor relies on things the Mosaic Law never even said. Yes, the Mosaic law said that people could put to death (by stoning, fire, etc.) those who transgressed the law, but it was not some type of vigilante justice like the letter sophmorically jokes about. Certain evidences/witnesses had to be brought before certain people for the case to be judged before a guilty or not guilty verdict could be given. Only after that time could the person be put to death. This is not unlike our system in method, only instead of police enforcing the punishment, the people did.
There were exceptions to this, such as a man killing another man who had committed manslaughter against his family, but that was only if the man who had committed manslaughter had left a specific city which was set apart for his protection (in other words, as long as the guilty man stayed in the city for a certain period of time, he was safe from harm (in essence, it was house arrest). But the exceptions certainly don't smack of the type of justice that the article jokes about.
Now, I do believe that there are difficult things in the Mosaic law, if it isn't taken "spiritually" (as I've seen most Fathers, except maybe the Antiochian ones, do). I said the Mosaic Law was not dissimilar to our system in method, but it certainly is in what it believes is a crime and how it punishes criminals. However, such a joke isn't going to bring these types of issues to light, nor help people grapple with their meaning. But then, this article was not meant to seriously bring up issues, but just meant as a childish joke. But it's not very funny, IMO, whether you're Jewish, Christian, or something else. Besides, from my experience it is generally not people who practice Judaism who would try to enforce the Old Testament laws, but Christian theonomists, who usually fall into the fringe of the Protestant Fundamentalist camp.