I don't think it's a "slippery slope of pornography somehow leading to cp" but rather once people realize that there is no moderation and no rules and no one wi

I don't think it's a "slippery slope of pornography somehow leading to cp" but rather once people realize that there is no moderation and no rules and no one will shut them down, it turns into the Wild West. If criminals learn that there are no police officers anymore, they know they can get away with committing any crimes without punishment. Since tumblr will host things other sites won't, eventually someone will push the envelope and if they don't get shut down it will get pushed further and further. It's not about "any porn -> child porn", it's a progressive furthering of what is/is not allowed, and once you learn everything is allowed and nothing is banned, child porn (and other illegal content) is an inevitability.