This didn't bother me. I assumed they picked that number _because_ it didn't work, to emphasize that only some numbers would end up back at the white node.
Clear, simple communication is a skill that takes time and practice to develop! Pointing out that you're not bothered by this strange example will hopefully be a good point for you to reflect on later.
Similarly, it can be difficult to recognize when you may come across as snarky and passive-aggressive. Perhaps it will be useful for you to reflect on this comment later.
This is the first example of self-recursive snark I've seen on HN. Congrats.