We definitely don't see every comment. Though I did reply in that thread.
The way to get us to see the comments is to flag them. To flag a comment, click on its timestamp to go to its page, then click 'flag' at the top. Alternatively, email [email protected] in egregious cases.
https://news.ycombinator.com/item?id=15297953
EDIT: Or maybe mods just can't realistically every comment.