Doctors without borders provide free labor to needy children in war torn countries. Programmers provide free labor to first world corporations worth millions of dolars.

> Programmers provide free labor to first world corporations worth millions of dolars.

The equivalent of this for doctors is called residency. It's an early stage in their career, during which they're laboring for free or being severely underpaid, in exchange for (sometimes) some experience, and finally for a stamp that certifies they're the real deal now - which lets them start charging for their labor properly.

Software career progression is less streamlined and less credentialized - there are many paths to necessary skills, and many ways of proving you have them. Open source work is one way to credibly demonstrate the necessary skills, and can substitute for or complement your education or work history in your quest for negotiating a higher salary.