It really depends on the subreddit, doesn't it? I only visit subreddits like r/boardgames and while there is the occasional rude person, overall thos subreddits are welcoming uplifting places. Some parts of Reddit are horrid and some parts are beautiful, just like real life. I just don't go to the horrid parts - just like I would avoid the horrid parts of a city.
I would encourage you to read any thread on harassment or the treatment of women and marginalized people in the tech industry and then revisit that thought.
Any thread about Facebook, and most threads about Apple are cesspools of negativity. I think you've got some rose tinted glasses when it comes to the kind of discourse that HN offers.