People saying drawing RnD seperated is ableist

I've been seeing a lot and I mean A LOT of posts saying that drawing RnD seperated is ableist and I really, really don't get how people come up to that conclusion... I just really need someone to explain their point to me because so far all I've seen people say is "do I really have to explain?" and provide no further context.

I don't see how drawing conjoined twins separated can be ableist and it's just really absurd to me.. Can anyone explain to me how they see it that way? I am actually clueless.