This is exactly right. I'm an engineer at the non-profit Mozilla Foundation, and these donations keep us working towards our mission (found at https://www.mozilla.org/en-US/about/manifesto/details/).
Its a big and divisive internal issue right now. :(
For certain things. But for badthink, seek and destroy.
https://static.mozilla.com/moco/en-US/pdf/2013_Mozilla_Found...
It's two years old, but if you go through it you'll see some very large numbers in the officer compensation lines, but it's mostly from "related organizations" and not the foundation itself. I'm not really sure how to parse it, and it may have changed in the last 2 years.