I could be wrong, but I think they're just poking fun at all the "An X interpreter written in Y" where X and Y are the current trendy languages. Usually one of X or Y are JavaScript or Go, so seeing both in the same headline is like some sort of Hacker News headline jackpot.
The comment was also probably poking fun. Yours too?
I'm subscribed to HN's RSS feed using a feed reader app on my phone, and when I saw this item the title was truncated at around "written." Somehow I just knew it would be Go.
I entertained the idea that maybe it would have been written in JavaScript, but I think a JS interpreter written in JS has already been done at least once.