I think it's a great letter - although I do think their is weakness in her argument about the use of the anti-emetic drug to trigger 'milk' production, in the narrow sense of its effect on the babies being fed - as it is prescribed to women struggling to produce milk, so there is years-long precedent for this off-licence use.
I don't have the links to hand, but I believe the dosages taken by women (under strict control) were a magnitude smaller than those taken by the transwoman recently
From the UK Breastfeeding Network:
The maximum dose as a galactagogue should be 10mg three times a day. This prescription should be reviewed at 7 days and further prescriptions should be considered at a reducing dose.
and from the single tracked induced lactation paper from 2018
www.researchgate.net/publication/322583718_Case_Report_Induced_Lactation_in_a_Transgender_Woman
The patient was started on domperidone 10 mgpo tid.....The patient’s first follow-up visit occurred at 1month....The domperidone dose was in-creased to 20 mg po qid...Our patient continuedto take spironolactone while breastfeeding...Throughout this process, the patient used domperi-done
(po qid means by mouth, 4 times a day, po tid = by mouth 3 times a day)
It's entirely different to inducing lactation in women - higher doses, longer term, and with other hormones/blockers.