I'll second dang in saying this is not true (thanks dang for the moderation by the way, it really does help, even if no-one agrees with every decision). Here's an example of a viewpoint you probably think of as part of the orthodoxy being voted down and flagged:
There definitely is not only one viewpoint allowed on these threads, with others flagged or voted down.
The threads attract more flagging and up/down voting wars than usual, but the votes are not all one way, and frankly if anything I think the comments on HN on these threads are pretty male dominated and hostile to the women concerned, plenty of those comments are allowed to stand.
https://news.ycombinator.com/item?id=14677258
There definitely is not only one viewpoint allowed on these threads, with others flagged or voted down.
The threads attract more flagging and up/down voting wars than usual, but the votes are not all one way, and frankly if anything I think the comments on HN on these threads are pretty male dominated and hostile to the women concerned, plenty of those comments are allowed to stand.