This is a constant problem for women on HRT and I've had the same with my GP. I live in NZ and for ages, every time I went to re-up my script, I'd get the spiel about coming off it etc. etc. But having kept up with all the studies, followed Dr. Currie's work, I feel confident that there is no 'reason' I 'should' come off it if it's benefiting me (which it hugely is!), given my risk factors are so low.
I actually started to get a bit ticked about this, and have had to be firm and my GP has mostly give up on nagging me about it, though I still hate having to visit her, and I gird myself for the attitude. One thing I did with my GP was ask "why"? WHY should I come off it? I got replies about breast cancer (wrong!) and afew other things, but really she had no argument, especially when I pointed out how I have zero risk factors (in terms of weight, smoking, etc. etc.)... In the end, it turns out it's just one of those GUIDELINES the GPs are told they have to follow on NZ, and they are essentially obligated to say "this should only be for the short term" ... but there is NO satisfactory explanation as to WHY, in my view.
I think what really got me in recent years has been the huge rise in young people wanting gender transition, and at one point I said to my GP, (in a bit of a rage, admittedly) 'how come a teen could come in here and get hormones to transition, but I, an adult female who's read the studies, informed herself etc. etc. has to be treated like I don't know what I'm doing?'
Bottom line, if you've done the research and know what you want and need, and what your risks are, stick to your guns and if your GP won't provide what you need, get a new one.