The female presenting nipples thing is complete bullshit. When tumblr chose to ban “adult content,” they had a chance to redefine what that means, and failed to take the chance. Female nipples and male nipples are the same, and a shirtless woman is not inherently pornographic.
My problems with the new rules go beyond that, of course. Most other social media sites try to present a safe-for-work, polite face to the world, so Tumblr’s old policy on sensitive content was unique and refreshing. It promoted artistic freedom, and allowed women to show their bodies without some of the typical sexism and shame that our society inflicts on them.
Bots were a problem. Child porn was a problem. But those problems could have been solved without changing Tumblr policy.