Just because someone have not commented on something does not mean they are guilty. They might not know about it. Some people live in the real world, with a large latency to news, e-mail or social media outlets. Yeah, I know, it is strange.
The post made the front page on HN a couple of months ago: https://news.ycombinator.com/item?id=7016735. DO staff seem to spend quite a bit of time responding to threads on HN in general, so that would be surprising.