Practically, because I just didn't notice, and the statement seemed unambiguous. Since it was a highest-level comment and a direct response to the post, "the author" was not a reference to person I was replying to. If I meant to talk about you, I would have just said, "you."

Subconsciously, the fact that I have no idea who he is, don't particularly care for that name, and feel that naming him would give him status that I don't believe he's earned all factored into my decision, though none at any conscious level.