Arguing against the mainstream position can even get your comment flagged. Doing it a few times (even about unrelated topics) will get your account banned for being "incendiary". HN is an echo chamber. But that's not surprising, all Internet communities are an echo chamber to some point.
Try an experiment: Argue in a thread that Facebook/Google/etc. are anything less than mustache-twirling-villian levels of evil, or that the people that work for those companies sometimes make actual human mistakes.