What do you mean no one talks about it? The media itself (and occasionally even the United States government) were taking about it a lot as they lamented the rise of Fake News and the election of Donald Trump. They asked for it, and suggested if they didn’t get it there might be heavy handed regulation. Facebook gave it to them.
A sample.
"What Facebook Did to American Democracy" — The Atlantic https://www.theatlantic.com/technology/archive/2017/10/what-...
"Facebook Has Been a Disaster for the World" — The New York Times https://www.nytimes.com/2020/09/18/opinion/facebook-democrac...
"Mark Zuckerberg Has Set Our Democracy on Fire" — The Nation https://www.thenation.com/article/politics/zuckerberg-facebo...
"Can Mark Zuckerberg Fix Facebook Before It Breaks Democracy?" — The New Yorker https://www.newyorker.com/magazine/2018/09/17/can-mark-zucke...
"Facebook harms children and weakens democracy: ex-employee" — BBC https://www.bbc.com/news/world-us-canada-58805965
“Fighting Digital Disinformation” - Warren for Senate https://elizabethwarren.com/plans/fighting-digital-disinform...