He changed his mind since then. https://www.stallman.org/archives/2019-sep-dec.html#14_September_2019_(Sex_between_an_adult_and_a_child_is_wrong)
Yet that looked as “excentrical” as his other uncommon views (about necrophilia, bestiality, etc. etc.), and was drown into these until now: too bad they become so publicized when he doesn’t support them anymore. Yet I’d like to note that doesn’t change that fact: he didn’t defend *exploitation* as you said, as coercion, rape, pedophilia, doesn’t imply exploitation. He even clearly stated in one of your quotes that he was against coercion. And exploitation is coercion. So it’s not logical. The main people concern is he was saying pedophilia was not implying coercion but could imply consent. He wasn’t even talking about rape. Note also that “sex work” imply money (otherwise it’s simply slavery (yet both work and slavery can be bad, as work as already been described as a form of slavery)), and a teenager is more likely to deal with money than a child, so that might explain the supposition.