I know why politicians don't care about the consequences of such actions, but I'm always surprised of the support here on HN for such actions, when the horrible, slippery-slope consequences should be obvious. Well...I do know of one reason, but I won't go down that political rabbit-hole.
(Or choose some of the other restrictions that Germany places on speech)
I suppose the ultimate sanction from Facebook's perspective would be to null-route any traffic from or to Germany. No news, no fines!
Losing 40 million users ( one-fortieth of their userbase ) would be a lot less painful to the company than what Germany's leaders would receive from their electorate.
Based on the slippery slope metaphor alone, the most you can say is that scenario #1 may lead to scenario #2. But the slippery slope is very often lazily and fallaciously used as the evidence or proof that scenario #2 will happen.
Now, just to point out, but "fake news" at this point has tipped elections and, in at least one case, led a man to go shoot up a pizzeria.
I like free speech as much as the next guy, but Germany has hate-speech and incitement-to-violence laws for a reason. In addition, if Facebook is going to work as a de facto monopoly, it should be treated with de jure public utility status. It's not a start-up competing against five other social networks anymore: it's the first or second most-trafficked website on Earth, and the single most common news source for internet users on Earth.
If there really were five different social networks with their own approaches to fake news and lively competition for users, I wouldn't favor state action until the line of incitement is crossed. As it is, Facebook holds a monopoly.
Those already show how difficult good rulings on these things can be, and they are IMHO a lot simpler than "fake news" since they don't involve truth-finding by courts, or even worse enforcement agencies, on the same level.
I'm really curious to see how the press is going to react to this. It doesn't make sense to apply these rules to an aggregator/sharing platform and not to news sources themselves, and as fashionable as it is to hate on Facebook they really should not want high fines (or even any extra state judgement) on "reporting the wrong thing".