Don’t apologize. This was a very fascinating read, and a good technical write up, especially for you first even HN post. It’s not your fault others didn’t look at the username :)
I was just about to highlight this particular HN quirk. I suppose a lot of people here only ever comment (or submit URLs without any text of their own) and aren't familiar with it.
They shouldn’t have to make it “obvious”. They are the actual author of the article. It’s not their fault you didn’t double check the usernames. It’s not uncommon for authors to comment on their own articles.