I have a unique perspective of this.
I'm a male. "hetero"
Clearly look male in appearance.
But i have a name in real life that can be used for males or females. Think of a name like Alex for example (not my name but an example)
As a result i am used to being "misgendered" all my life. I get mail adverts addressing to myself but using Ms or Mrs.
Receptionists or Teachers usually call my name before meeting me for the first time asking for a woman instead of a man sometimes.
Unsolicited robo calls leave me messages sometimes asking for a ms or Mrs.
And i have never been bothered by it or taken offense. I alway assumed people just did that because they didn't know. Once they do know they correct themselves. Same thing with Trans people, people are calling your sir because you appear to be a man, they can't tell just by looking at you that your prefer another name. No hostility in it, people just can't read minds and operate off assumption,
Its when you inform them and they refuse to correct themselves that they are being problematic. And what she did here was exactly that. Intentional misgendering someone. Can't really see this as her making a good point. Its just doing that same thing she is complaining about.
Conclusion being 1) Some people make too big a deal over an honest mistakes. Its not their fault you willingly selected a pronoun that doesn't align with their outward appearance, People can't read minds. 2) Intentional Misgendering is not a good counter argument, just hypocritical. You are doing the same thing you complain about.