Probably because "hermaphrodite" is considered a slur to intersex people.
Also intersex and non-binary are not remotely the same thing. Some Intersex people are non-binary but a lot of them have binary identities. It's a different axis.
How do you figure that? Also "hermaphrodite" is not the accurate term - that would refer to an organism which creates both gametes, which humans never do, even intersex ones.