so far, the issue has been engagement results in ad impressions, and the quickest way to engagement is controversy and anger. The death knell for Facebook was when it became people arguing all the time. Toxicity is just generally not pleasant to be around.
Ad quality also doesn't help. Major network TV ads are generally higher quality both in terms of the product they're selling and the production quality, but I don't want to see the millionth ad for meal prep startup of the week or questionable unitasker dropshipped off Aliexpress.