[commandlinefan]

Depends on the case, but as far as I can tell, most of the time comments are flagged and removed, it's because too many people disagreed with the poster (including the HN moderators), rather than somebody spamming the site, so yeah, a lot of the moderation here is censorship in any way you could define it. You see this over and over again on public forums: a means of controlling spammers who are not actually participating in what the forum was designed for is introduced and is immediately abused by people who want to limit actual participation.