There is a lot more groupthink and echo chamber behavior on HN compared to Reddit due to the way flagging works. For me, HN is unusable without using showdead and using the active front page so I can see what stories its userbase tried to flag off the normal front page.

You can also say some pretty horrendous things on this site as long as you couch it in modest proposed-esque soft language. If I want to have a non-technical conversation with other human beings, Tildes blows the doors off of HN in the empathy department.