Because we didn't see any of this. We can't moderate what we don't see. That's why the site guidelines ask you to flag comments that shouldn't be on HN, and in egregious cases to email [email protected]. To flag a comment, click on its timestamp to go to its page, then click 'flag' at the top. (You need karma > 30 before flag links appear.)

Please see https://news.ycombinator.com/item?id=21003570 and https://news.ycombinator.com/item?id=21003591 for more.