Nicole,
Your story is not that uncommon. I am having an issue with my Primary Care Physician right now. She used to prescribe my Estradiol, but now that I am 69 year old, she is concerned about cardiac issues. There is a recent study that show that trans women taking Estradiol have a 16% lifetime likelihood of having a heart attack, compared to 13% for normal men of the same age group. She felt that this was too dangerous to prescribe for me, even though the Estradiol is very beneficial for my gender issues, prostate issues and bone demineralization.
Fortunately, I have an Endocrinologist who is fully in agreement with my needs and has prescribed Estradiol for me.
When any doctor refuses to prescribe a particular medication, that is based on their opinion. Are the benefits worth the risks? For myself, the answer is yes. From my PCP's perspective, she is not in agreement. This is not a matter of competence, but rather on what is most important. All doctors do get requests for sometimes unreasonable things, but a request for HRT from a transwoman with an established history seems reasonable.