The definition of paraphilia is "a condition characterized by abnormal sexual desires, typically involving extreme or dangerous activities.", which can inclde pedophilia.
The lemmy.ml devs were ok with Nazi instances being on join-lemmy "because people can just choose to join a different instance if they want" (or words to that effect) so it'll be interesting to see how far they take that line of reasoning.
This isn't a censorship issue. This is a choice about whether to publicise and promote pedophiles or not. No website has a right to be included in join-lemmy listings.
They're as leftist as the "communist" China. Or as "socialist" as the Nazis were. Just because someone calls themselves "communist" or "socialist", doesn't mean it's true. And if you support China, Nazis, Soviet Union or its successor Russia, you're not a communist or socialist.