From Edit Profile & Settings, we have below information
Hide Communities
Choose which communities will appear in the Communities and Top Network Posts sections of your profile
Hiding a community means other users will not see it in your Communities list or Top Network Posts. It does not, however, mean your activity is private.
So it is clearly mentioned
Hiding a community means other users will not see it in your Communities list or Top Network Posts.
But, I could see the top network posts are taken from hidden communities for ex: I have marked 'Christianity' as a hidden community in my profile. But, the top posts has a question taken from Christianity community "Which tribe did Paul belong to?"
http://stackexchange.com/users/{replaceUserID}/
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