Isn't this the wrong way round? You get the 404 page if either they broke something or you can't type.
True. Such backwards "Venn diagrams" are actually pretty common. See also, on this same site, "Children Dangerous Things", "Smalltalk", "Royal Affair", and probably others.
Venn Diagrams are like Irony - far more people use the term than actually understand what it means.
Most of the diagrams on that site aren't Venn Diagrams at all - some are just...gibberish.