Because, like it or not, Facebook has become a trusted news source. Because of that, they have a duty to accurately report the news.
Their human editors fell down by vanishing stories they found politically uncomfortable.
Their algorithmic editor fell down by promoting stories that were false.
What other trusted news source has this "duty?" What other trusted news source does not have biased editors?
All of them.
> What other trusted news source does not have biased editors?
None of them, of course. Man is a fallible creature.
But other news sources try, most of the time, to be objective and accurate.
Because, like it or not, Facebook has become a trusted news source. Because of that, they have a duty to accurately report the news.
Their human editors fell down by vanishing stories they found politically uncomfortable.
Their algorithmic editor fell down by promoting stories that were false.