They’re just asking what you prefer. If you don’t like the term chestfeeding don’t use it. Surely it’s that simple? Whether you like it or not some trans people have kids, and they’re entitled to have their preferences met just as you are. It kind of sounds like you’re offended about other people being treated with the same respect as you, and that is really unreasonable.
This is the whole crux of the TRA movement. Why ever would/should they ask a woman whether she wants to use the normal accepted term or a bizarre, inaccurate term invented so as not to upset people who identify as men and NOT women - people, that is, who are doing what obviously only a woman can do?
In the case of a pregnant transman, it will be in their notes (and likely obvious) what their status is. By all means let HCP ask this tiny fraction of patients which they prefer. I once read of a man who lived as a cat and wanted to be treated like one. Does this mean that every reference to the word 'person' should be removed from all government forms and documents - just in case this man or somebody like him happens to turn up requiring their services? He might be dreadfully upset and offended if anybody assumes that he is human.
Therefore, do we end up with forms that go on for pages and pages asking "What is your preferred pronoun - he, she, they, it, hem, haw, zim, zam, zem, other?"; "Are you a human, cat, dog, giraffe, rhino, mayfly, lady/man/non-binarybird?"; "Should we refer to your upper limb extremities as hands or paws?"; "Are you Black, White, Asian, Oceanian, Eurasian, Narnian, Liliputian, offended by the suggestion of racial compartmentalisation?" ???
Is it really so difficult to treat the virtually-whole majority in a standard, accepted way that suits the virtually-whole majority perfectly and make individually-tailored adjustments for the handful of patients/customers who may require them?