It's more than just not ideal - it measures the wrong thing entirely. Yet finding a better measurement is difficult. This 2015 survey claims conservatives are less likely to share their unpopular views on Facebook [1], and this 2020 report claims Facebook News leans left-center [2]. But neither measure the traffic of conservative vs. liberal news stories on Facebook, so it's risky to draw any conclusions on that. On the other hand, they ban white nationalism entirely [3]. I'm not sure it counts as conservative today, but it was official US policy until 1965.

[1] https://civicscience.com/is-facebook-changing-the-political-...

[2] https://mediabiasfactcheck.com/facebook-news/

[3] https://www.theguardian.com/technology/2019/mar/27/facebook-...