First you claimed "until relatively recently, the terms "gender" and "sex" meant essentially the same thing and could be used interchangeably" which is objectively incorrect and you've ignored that I pointed it out.

You also claimed that gender is some sort of scientific concept, which is also objectively incorrect.

If someone asks you to call them by "him" and you call them "her" instead, you are just being unnecessarily mean. This is not a hard concept to understand, be polite to others if you don't want to face problems in your personal life and career. Refer to people as they wish to be referred as. Asking you to do that is not "vocal, vicious and vindictive... [people] ...enforc[ing] their own cultural taboos" and quite frankly I find it disturbing you think is it.