Because not all the words that are gendered refer to a single gender. I understand when we change the last vowel to an e to add a non gendered version of a word that has both male and female forms (e.g. nosotros/as, spanish for "we", would do great with a nosotres). But when the word itself is already non gendered (as persona, which although is considered female, refers to any person of any kind, because there is no male alternative) I don't see a reason to do it.

There is no discrimination in referring to someone as a persona, since there is no "persono" word, so saying persona no binaria will offend only who wants to be offended.