Why are doctors so reluctant to write something for the VA even when it's their assessment?

So going to complain here. The VA referred me to nephrology because my kidney markers were skewed and despite being on 3 different blood pressure medications my blood pressure is high.

During my assessment the nephrologist basically said it's because of my excessive muscle mass and that my blood pressure was hard to control because I inject testosterone. I'm service connected for low testosterone.

After I messaged him asking if he thought there was an equally as likely as not chance that my testosterone treatment exacerbated my hypertension. He responded saying there were multiple ways it could but to keep taking testosterone.

I responded asking if he thought in me if there was a 50/50 chance it was making it harder to control blood pressure and explained it wanted to know because if so i could link it as a secondary claim.

He responded saying it was a primary and not caused by testosterone but testosterone made it worse.

I said I get that and just asked if the testosterone made it worse in me, 50/50.

He said yes.

I asked if he could write a letter stating that the testosterone treatment which I'm service connected for had an equally as likely as not chance of of making it harder to control my blood pressure.

He said he would send his notes to my primary care provider to do with as she saw needed....

I got annoyed and sent the following message:

"I think there may be some confusion. The request is with regard to veterans benefits purposes, not medical purposes. For me to move forward with the benefits process the opinion of a specialist is what's required. My primary care has no say in the matter of what's needed as she deals with Healthcare, not benefits and since my primary care provider is a VA employee, some might say there's a conflict of interest there. "

Was i out of line? Why was this such a run around the whole time? It's his medical opinion, why is he afraid to state it?