I'm not defending Facebook but I have yet to see any substance to the argument that they are manipulating the conversation on their platform.
But here is one about Germany - https://www.theguardian.com/technology/2016/feb/26/mark-zuck...
Though to understand what it is really talking about, you have to understand the redefinition of "hate speech" that has happened through-out the EU.
As an American this is especially interesting to me because we place such value on our freedom of speech but also pay a high price in the hate speech that is viewed as a necessary evil. It seems that the EU has made an attempt to manage this hateful speech but I'm not familiar with the specifics.
German blog post about it: http://www.internet-law.de/2015/09/muss-facebook-staerker-ge...