The only way to detoxify the internet, is to get rid of the "social" aspect. Starting with gasp comments. My online experience has been that much better, since adding comment blockers to my browser.
Reddit has a large user base and a myriad of subreddits where different solutions have been tried. So far, the best I've seen is strong moderation: clear rules and swift enforcement. AskScience is a shining example of a high quality subreddit, although the comment section usually looks like a graveyard with 90% of the comments removed.
That kind of moderation works under those environmental conditions - similar how some drugs work on certain types of body types and fail in others.
Other topics which are broad and have little general boundaries tend to get a lot harder to define.
Classic example would be where does porn stop and art begin?
In forum terms - politics, general opinion topics have more subjective moderation.
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Overall though, I agree - manual moderation is pretty much the best way to go forward.