its a scientific classification for how the fetus conducts itself in utero. you are likely attaching the stigma of the word “parasite” to what is a correct categorization for this scenario. its actually not extra because if she compromised an called a fetus a baby, he wins.
non-binary ppl arent expecting strangers to know their pronouns, we just ask that you refrain from explicitly gendering ppl before you know their pronouns.
if that request angers you, i believe that has more to do with you than it does with us.