Precisely because those are ads, not submitted stories. See the HN FAQ¹:
Can I post a job ad?
(…)
Another kind of job ad is reserved for YC-funded startups. These appear on the front page, but are not stories: they have no vote arrows, points, or comments. They begin part-way down² and fall steadily. Only one is on the front page at a time. The rest are listed at jobs³.
However, you can still voice your concerns about YC companies on other threads. Again from the FAQ:
Are negative stories about YC suppressed on HN?
No, we moderate less, not more⁴, when YC or a YC startup is the topic. The good will of the community is worth more than any story.
Comments
Precisely because those are ads, not submitted stories. See the HN FAQ¹:
However, you can still voice your concerns about YC companies on other threads. Again from the FAQ:
So go for it!
¹ https://news.ycombinator.com/newsfaq.html
² I think I remember reading they start in fourth place.
³ https://news.ycombinator.com/jobs
⁴ https://hn.algolia.com/?query=moderate%20less%20not%20more%2...