Gail, estrogen taken orally has a significant effect on likelihood of throwing a blood clot and of course surgeons are going to want to eliminate all possible risks (liability issues are going to dictate this).
Being conservative creatures, even if you take your estrogen by injection or transdermal patches - which are functionally equivalent to a natal females - they still want you to discontinue. And because the release is delayed with injection, in my case the doc had me stop a month in advance of surgery, would have been 2 weeks if I took pills.
It's only a month and honestly post-op you're gonna have other stuff on your mind. Yes that month sucked for me, the moreso because I had a huge amount of work and absence of HRT sure doesn't help my coping skills. Flip side for me was I dealt with it - I was effective, scheduled well and stayed organized. Those wouldn't normally be my strong points and that I managed sure told me how motivated I was to get to Dr Wittenberg's door on April 26 :-).
And post-op, I have to say, HRT was pretty low on my list ... not that I didn't think about it and the peace of mind and return of my more emotional self was truly welcome but the day I was permitted was also the day we had to take a 25 mile Uber trip for the first post op appointment and. I was so tired, I didn't get to doing my injection until the next day.
Hugs &c
S