I was going to reply privately, but could find no contact details. I see you espouse HN Notify, so I'm hoping you'll see this response.
My duplicate detector found the initial pair almost immediately. I did nothing, because there was no discussion, so I didn't know which one to point to. Then the third came. Still no discussion. I watched in considerable dismay as a submission that I thought was absolutely excellent, and deserving of significant discussion, sank without trace.
Was it just unlucky? Did no one read it? There were a few desultory upvotes - a few had read it. But was I so completely wrong about what HN would find interesting?
I couldn't believe it, so I submitted it again over a month later. Still no upvotes, still no discussion. It seemed I was wrong about the audience here.
And now I can see that I was right about HN being interested in deeply technical issues like this, and I'm happy. I'm less happy that a brilliant item like this took four submissions, sorry, five submissions before it got noticed.
That's why now I generally try to point out duplicates in two circumstances. One is when they come close together, and that's to help stop a split discussion. The other is when there was a significant discussion on an earlier occasion, and I want people to benefit from previous comments.
So no, I don't think it's a case of glass houses.