The point is, that the author is trying to point out Hacker News - a discussion forum - is toxic for having a reflex to give contrarian opinions. Wheras the aut

The point is, that the author is trying to point out Hacker News - a discussion forum - is toxic for having a reflex to give contrarian opinions. Wheras the author is doing it in real life in settings where not both parties agree it is a discussion in the first place. That is the toxic behavior, but he tries to paint HN as being toxic.