Ask HN: Why so many low point, comment-less posts in hone page?

Lately, navigating the home page, I see a lot of posts with relatively low points (around 5-10) and low comment count (many at 0). Shouldn't a post be discussed and up-voted before reaching the home page? Are they manual insertions by the mods? (I'm not complaining, just genuinely curious).

Examples in home page atm (not exhaustive and obviously prone to change, now that they're in home page):

https://news.ycombinator.com/item?id=38590164 - 3 pts, 0 comments, ranking 7th https://news.ycombinator.com/item?id=38590144 - 5 pts, 1 comment, ranking 8th https://news.ycombinator.com/item?id=38574174 - 4 pts, 1 comment