Yeah, that is offensive. I'd like to know what episode it was.
Some people I know like to call transgenders by what they "look" like the most. So, like me, I'm not on T, so everyone knows I have a female body, and it makes it more natural for them to want to call me "she" and once I'm on T and my voice lowers, it will be more natural for them to want to call me "he."
Not trying to defend them. I think it's just ignorance.
I did see this one Law and Order SVU episode that I did like. It was about these male twins. but one of the twins had a "circumcision accident" where he lost his penis. And the parents met some freak doctor who convinced them that it would be best to raise the baby as a girl so he didn't have to grown up as a man without a penis. And the kid was now a teen in the show, and was completely miserable.
Anyway, the reason I liked the episode was because I was actually watching it with my grandma, who is very much against gays and trans and doesn't know that I'm trans. But the show allowed me to talk to her about trans and intersex people. Because my grandma believed that what the doctor in the show did was wrong and that the boy should have been raised a boy. And I started talking to her about intersex people and then trans people. She kinda stopped talking, but I could tell she was thinking. Maybe she won't be so bad when I finally come out to her.