For the other statements, I dont think he's "endorsing" it, he's raising questions. I'm not AT ALL on the same boat as him wrt this topic, but I dont mind a discussion on this topic. I consider that the basis of democracy.
Also, from this recent interview on the register it shows he changed his mind on this topic: "Many years ago I posted that I could not see anything wrong about sex between an adult and a child, if the child accepted it. Through personal conversations in recent years, I've learned to understand how sex with a child can harm per psychologically. This changed my mind about the matter: I think adults should not do that. I am grateful for the conversations that enabled me to understand why."
https://www.theregister.co.uk/2019/09/17/richard_stallman_in...
I respect that people openly change their views.