Why, every time someone suggests a fix to something they see as a problem (regardless of whether it's actually a problem, or even the merit of the solution), is there no shortage of people saying "yeah but what about these unrelated problems?!"

I think everything you suggested is something that should be addressed in one way or another. I think banning the sale of medical data is probably a good thing more often than not. All these things can be true, but responding to a statement about banning the sale of medical data with "yeah well what about the post office?!" seems weird, and perhaps politically motivated.