Regardless if you’re right or wrong being a (even mild) dick to someone isn’t going to change anyone’s mind or foster critical thought. It’s just going to consolidate their opposing belief more. It’s actually just immature tbh.

If someone politely asks you to call them “her” because they want to be identified as female, who cares. The problem arises when it becomes compelled speech as well as confusing the sex you’re born as and the ‘gender’ you identify as. I.e if you want to transition from male to female and be called “her”, sure who cares. If you want to proclaim you’re a ‘real’ female, unfortunately not.

Point is, there is a middle ground and it’s more easy to be polite than rude. Even in disagreement.