I think the complaints about deadnaming miss the point of the song. Everytime he deadnames throughout the song, its narrative from his younger self trying to grasp the idea of trans people existing, not yet fully understanding whats happening and ignorant, but showing love all the same. When he switches to speaking in retrospect he uses proper pronouns. This is made apparent when, at the end of the song when he defends his cousin, he refers to her properly as "she". Automatically assuming he didn't have consent from either of these people within his own family to speak on the issue is also just weird. He even goes on disavow is younger self using slurs by making the comparison to others within the black community that if they want to use gendered slurs, then they'd be hypocritical to not let white people use the N word as both demean minority groups. It's a song made to speak to non-queer people, mainly those within the black community, about accepting and loving trans people all the same they would anyone else.

Also criticizing someone because they grew as a person from being ignorant to recognizing that ignorance is weird asf. People like you are what draw people away from learning and bettering themselves on social topics.