I understand how the system is supposed to work. However, I am doubtful whether it will always work that way especially in cases of politically, religiously or racially motivated posts. There have been many cases on FB itself where FB failed to identify such fake news which created widespread disruptions and rioting. Fake news specifically manufactured to incite violence is extremely hard to control. High SP is no sure guarantee of wisdom and cannot be relied upon to stop the spreading of such news. On the other hand, upvote by a whale can help spread such fake news.
Experience on Steemit of how low quality content by certain whales still make the trending charts shows that it's not always easy to stop spread of undesired content.
Point is, we will actually have to wait and see how this unfolds. It can turn out to be a great control on fake news or can add unnecessary fuel and aid it's spread.