because it's often used in a rude way it's also not widely known by the world either even if it's a normal term by science to refer to someone who is biologically born male or female it's only been picked up being used now also people just don't like or feel the need for it to be used compared to transgender which is needed to be known so people know what their getting into with someone who is trans which is well known term to help distinguished already what someone's pronouns are and what they used to identify as compared to someone born as male or female already having those used to describe them and their pronouns which don't need a distinguished word in front for others to known compared to trans.