Hacker News is aggressively moderated, it's very much "quality over freedom" as far as speech goes. I don't know why people keep expecting it to be like 4chan, just because it has "hacker" in the title.
One thing is flagging (just like this), another thing is showing a different version of the site based on the user, the latter is scammy and is meant to give users the felling that their post is there (while it's not) but no one is looking at it.
Showing a different website to users is something really nasty.
Showing a different website to users is something really nasty.