Facebook fake-news writer can cause a strong impact on elections. This is because people can easily sway their opinions depending with what other people say. Facebook is a social media where lots of people interact and get opinions from the rest of the people. Due to this, it can be the worst influence.
The Facebook fake-news writer shouldn't have a strong impact on elections, because ultimately, the public makes up their own minds. If the recent election of Trump has taught us anything, it is that the public is confident in making up their own minds, other than and apart from the media. The media is not in the driver's seat.
If this election proved anything, it's that people can live in their own internet echo chamber and not have a clue what's actually going on in the world. This comes from a reliance on one source, especially when that source has an algorithm that shows you only the news that you are interested in. Voters (and other citizens) need to get news from a wide variety of sources in order to have a well-informed opinion.
In my opinion, Facebook is morally responsible for the content on its site. While it may never be known whether the fake news on Facebook played a decisive role in the outcome of the election, Facebook nevertheless is not blameless. An important principle of democratic elections is that voters are well and accurately informed. Facebook's fake news contradicts this principle.