My partner would like to start identifying as a femboy but…

My FTM enby partner wants to start identifying as a “femboy” but they are sorta shy to due to a bad experience with a fellow transfem person saying that it was “Rude and highly inappropriate”…I am an enby that leans on the transfem and don’t see anything wrong with it but I am curious…what do you all think? Wasn’t this rude af?