> Heavy moderation (/r/askhistorians) and niche (this forum?)
I'd consider these two to be both niche and heavily moderated: history is a niche topic too, and HN is heavily moderated.
> they are not the solution for the most "public" and mainstream places like comments under posts on BBC's Facebook page
I think heavy moderation is a solution, probably the only solution. But these places would have to implement it first. Moderation doesn't scale, and companies like Facebook only want to do the things that scale. Their toxicity problem is self-inflicted - they don't want to pay for what's needed to solve it. See my tangent in https://news.ycombinator.com/item?id=27917473.
I'd consider these two to be both niche and heavily moderated: history is a niche topic too, and HN is heavily moderated.
> they are not the solution for the most "public" and mainstream places like comments under posts on BBC's Facebook page
I think heavy moderation is a solution, probably the only solution. But these places would have to implement it first. Moderation doesn't scale, and companies like Facebook only want to do the things that scale. Their toxicity problem is self-inflicted - they don't want to pay for what's needed to solve it. See my tangent in https://news.ycombinator.com/item?id=27917473.