No, people and politicians are killing democracy.
People choose to get their news from unreliable sources. They act like they care about an issue yet only know the headline. But they can sign an online petition and post it on social media so they look and feel good.
Politicians can openly lie on the largest of stages. When called out on it (which rarely happens) they can stick to their lie despite opposing evidence. And they win because of it. A good example of this was the claim during Brexit that £350m per week would go to the NHS if we left the EU. After the referendum was over one of the leading figures admitted on TV that the claim was BS. When you can win by openly lying to the people, why wouldn't you? I think in situations like this elections/votes should be re-run.
My point is that Facebook has nothing to do with democracy. There are plenty of alternative news sources, some that are even reliable, and people instead get their news on Facebook because they don't actually care.