So, considering that that's what they all say, it is really probable no one truly knows why Tumblr is executing this FOSTA has been blamed, and so has Apple's application retailer gatekeeping methods. Rightly so, because Apple's purpose in censoring and suppressing sexual speech is longstanding, and so vile and insidious that it'll make you rage-smash an Iphone if you acquire it all in at at the time.