Slight correction: there were 2 cases, historically, of people with fully functioning sets of both sets of reproductive organs. I still wouldn't use the h-slur for them, but I don't think it's good to treat that possibility as impossible. It runs the risk of making anyone who does have those traits feel bad. I know it might sound like a conspiracy theory, but I've always doubted it was JUST these 2 people. I think there were and are probably others, but because IGM is so common they were forced out of having those naturally occurring bodies and traits.
And the really sad thing is that if you read up on the 2 people who had what scientists insisted on calling "true h-slur-ism", scientists speculate openly about "can this person impregnate themself?" like those aren't people, just medical experiments at best, fetish fuel at worse. It's so dehumanizing. I think the reason other people with this haven't come forward, in addition to IGM, is fear of being treated like that.
I would love the resources on these cases since this is deeply interesting (regardless of how full it is of intersexism)