I agree with the sentiment of your comment, but I don't think it was necessary. There are better ways to put it, and several of them have already been made.
A higher level of discussion and low noise is something to shoot for on HN.
I disagree. The passive aggressive nature of the post needed to be pointed out. It is at the heart of what is wrong with this post. This was not just another letter that "pretty much anyone signing the Dear Github letter would also feel comfortable signing" as the OP would now like you to believe, but a passive aggressive response to the constructive criticism of the original, as evidenced by its tone, timing, and context.
A higher level of discussion and low noise is something to shoot for on HN.