From what I understand, tumblr is kind of a money-sink for Yahoo. The userbase here rarely clicks on ads and that’s kind of the only way they’ve tried to monetize the platform. I think the blanket ban might be an actual legitimate attempt to shut the site down without giving the whole story to its users (and obviously being taken off the app store didn’t help revenue or visibility). If most users leave they can say “welp the time of microblogging has come to an end” and quietly shut the site down while we all say “I told you so”, not realizing that’s what they wanted all along because we aren’t making them money.