The question was "what term annoys you" not "what term annoys you that you're sure Lemmy will approve of" (or that a malignant narcissist billionaire isn't also annoyed by).

Nowhere in that question does it say you are free from being criticized for your dumbshit worldview. It's a public forum, you write something, don't get surprised when people respond.

To me it's like if I say I enjoyed the sunrise" and someone says, "you mean the Earth sunrise?".

That's incredibly weird. To me it's like someone saying "I'm trans, and you?" And the other responding "I'm cis." Funny how that works.

I'm open to an explanation of a commonplace situation where it's necessary to have a separate word for "is of the gender that matches that assigned at birth.".

See above. Also see: Whenever you need to classify yourself as cis-gender in any survey, form or likewise.