Definitely reply & provide documentation. There was something posted on FR early today (IIRC) that said MILITARY studies show ivermectin is effective at every stage of covid.
Then I would certainly let this doc know you’ll be looking for another one.
These large, interconnected hospital systems could put a negative remark in a complainer's computerized file that would be like a blacklisting. It's better to just quietly find another doctor and request a file transfers from the assistant without making a big deal. You need not give an explanation.