As a physician, I plan to volunteer at free health clinics and do what I can to help out in my community. This is very different from being a part of health care reform. Though I think it's important to know the basics, I was just making the point that not all physicians want to be involved in making changes to our current health care system. In fact, most physicians don't have the power, time or money to do so. It's really in the hands of politicians, insurance companies, hospital administrators, and lawyers. It's clear that this isn't the best case scenario, but it's the reality of our current system. I will financially support physicians with that kind of energy and passion, but personally it's just not something I foresee as being a positive experience.
What's more, my application shows absolutely no interest or experience in health care politics or administrative work. Every applicant is different. Not every applicant can spend 2 years in the Peace Corp, publish scientific papers, volunteer 1000 hours, and have years of clinical experience. Each applicant brings their own interests to the table, and I think interviewers appreciate that. If you don't have an interest in being part of health care reform or getting an MPH (and/or don't have experience working in a related field), then I don't see why you shouldn't be okay with just a basic knowledge of health care reform.