The difference is that police officer and firefighter are roles that can be occupied by people of either sex, so the change of language from policeman and fireman made sense in that context.
By contrast, pregnancy is a state of being that is by its very nature female-only. Males cannot become pregnant, as by definition they lack a female reproductive system.
The "pregnant people" terminology implies that pregnancy is something that affects all people, male and female alike. But this is of course not true at all.
It's also not inclusive - consider that much of the sex-based oppression women experience goes back to the ability to conceive children. "Pregnant people" discards and downplays all of that.
Some people have unusual chromosomes, ie. Not women or men's, and they can still get pregnant. Other people transition but still have kids. Sex or gender; the language can apply just fine to anyone who gets pregnant and is appropriately vague. I am fairly certain the term isn't one of disrespect to women's rights or accomplishments.
Regardless of sex chromosome aneuploidies or a desire to be the opposite sex, everyone who is, who could be, or who has ever been pregnant is female.
Another point against using the phrase "pregnant people" instead of "pregnant women" is that it leaves no way to talk about women who aren't pregnant. "Non-pregnant people" includes every man and every prepubescent child.
> Regardless of sex chromosome aneuploidies or a desire to be the opposite sex, everyone who is, who could be, or who has ever been pregnant is female.
That is _your_ definition, and it is very debatable.
>Regardless of sex chromosome aneuploidies or a desire to be the opposite sex, everyone who is, who could be, or who has ever been pregnant is female.
Nature disagrees with you. There are many animals out there that can change sex. Sex, gender, etc etc don't have a perfect universal definition because nature doesn't work that way. The scientific literature is trying to capture the observed variety we see in humans and it will continue to evolve as our understanding evolves.
This whole line of argument reminds me of the history of pi and the governments that tried to legislate it to fixed values. Just because you want things to be simple doesn't mean that reality backs you up.
We're talking about humans. That some other animal species have a reproductive strategy of sequential hermaphroditism is not relevant to the conversation.
Police officer and firefighter are pretty ingrained now, but those weren't the dominant terms just 30 years ago