Nothing to do with toxicity whatever that means. All forums had moderation and some had more of it and some had less, so people could choose their favourite sweet spot.
It's mobile phones - in the hands of billions of people. You can't spend time researching and debating on a forum in-depth like we used to, because the small screen has it's limitations compared to a pc in 90's and 00's.
And the contingent of people who had PC's and internet at that time were smaller and more of a different breed compared to the average internet user as of now, with a phone in their pocket.
And probably because big corporations turned internet into a Cable TV v2. with reactionary surface level comments under the content you tune into - contrasting to a free communication tool as it used to be.