Because it's explaining the wrong confusion. People who are confused about pointers and arrays in C don't think that the concept of a pointer is the same as the concept of an array - they think that in C, the two have the same semantics. That explanation and analogy do nothing to explain the semantic difference, and honestly come off as a pretty condescending by essentially saying "Well they're different things, of course they're different!"

The poster probably did not help matters after that by calling the downvoters "clueless n00bs" or making a self-righteous statement about how they won't delete the comment just because of downvotes. That kind of toxic behavior just ensures that you'll get more downvotes.

Because the number of people who believe that arrays are pointers vastly outnumbers those who don't, and many of those clueless n00bs have karma >= 500 on HN, or whatever the level is to be able to downvote. Judging by one answer, some people don't believe that the comment could even be about C, so wrong it must be!

Nope; I simply refuse to delete a comment that is civil and correct just because of some fluffy downvotes. It stays and that's that.

I suspect it's downvoted for the mention of Betteridges Law of Headlines, which (rightly) earns downvotes whenever it's mentioned.

Look, it even worked for your comment! Must be true.