No one advocated "putting your healthcare decision in the hands of an LLM." Answer the post that was written, not the one you rewrote in your head to conform to your biases.

Current frontier LLMs are incredibly powerful diagnosticians. They will generally give you the best assessment that can be made on the basis of the information you include in the prompt. So it's important to make sure that information is accurate, and also that it's phrased well enough to allow the model to weigh the importance of each detail.

Unsurprisingly, the same tips are important when communicating with your actual doctors.