How to convince someone that health insurance companies are not the devil?

[MoProblems_MoMoney]

So, one of my friends saw Sicko and is now convinced that if I work in health insurance, I'll be working for the devil. How would you go about convincing her otherwise? Specifically, she's convinced health insurance companies are about making billions in profits and living the life of luxury by exploiting sick, dying people through denying their claims/refusing to write policies for people with pre-existing conditions.

I'm not a troll, I promise. I've tried to argue with her, but I could really use some tips from people who work with it firsthand.