This is not censorship in the way the word is usually used. The contents of HN's front page are mostly determined in a democratic, automated manner based on use

This is not censorship in the way the word is usually used. The contents of HN's front page are mostly determined in a democratic, automated manner based on users' upvotes and flags. Some topics are, in the eyes of the people voting and flagging, not suitable for the front page. It has to be this way because the amount of content submitted is many many times greater than the amount of space.