they didn't say why.
http://dailycaller.com/2016/07/25/facebook-admits-it-censored-wikileaks-dnc-email-dump-but-offers-no-explanation/?utm_campaign=atdailycaller&utm_source=Twitter&utm_medium=Social
Facebook admitted Sunday that it blocked links to WikiLeaks’ trove of emails that were hacked from the Democratic National Committee (DNC).
WikiLeaks took to Twitter Saturday night informing followers that Facebook was censoring content and offered people an alternative way to post links to Facebook from WikiLeaks.
....
One Twitter user explained that, “Facebook has an automated system for detecting spam/malicious links, that sometimes have false positives.” Facebook’s Chief Security Officer Alex Stamos acknowledged the censorship and tweeted at WikiLeaks Sunday, saying the social media giant “fixed” the problem.