Perhaps I'm in my own echo chamber, but I definitely view open source contributions on a resume as a huge positive when I'm reviewing resumes (as a software dev my boss trusts to evaluate applicants), and I had thought that if that wasn't at least the norm that it would be pretty common among tech companies / companies where developers are part of the evaluation process.

edit: Also, all of the open source I do or that I know of my peers doing is 100% for the love of programming and open source culture, without a bunch of hidden motives. Open source was definitely key to me becoming a programmer when I was a kid - without it I would never have gone as deep as I did into coding (linux, gcc, irrlicht), 3D modeling (blender), etc.