It would be okay if someone like, stood up and said that they were being ignorant, but no one did. And it makes it hard to tell if he’s really trans*, or if he just has an alter ego or whatever. Because he isn’t really upset about it.
It’s unclear whether or not he’s trans* but regardless, calling them he/she is really rude, I don’t think they were called he/she to their face, if they did and brushed it off it would’ve been different.
But…eh, Glee being tactless and stupid as usual, not surprised.