User blog comment:Rappy 4187/Technical Update: November 16, 2016/@comment-146.198.29.151-20161117163147/@comment-1824272-20161118215819

They have analytics that track clicks on almost everything on Fandom. If their data says the social media buttons were rarely used, then that's the case. And I totally believe it, there aren't many circumstances those buttons would be used for wikis.