[kmike84]

Choosing a company to work for is not beyond one's control. It is possible to specifically look for a job that allows contributing to open-source in some way, or, in other words, to blacklist those who explicitly forbids that. I've done this in both two cases I was on a job market and still enjoy this decision.

Maybe I see the world through rose-colored glasses, but I don't see why sane employer would like to forbid contributing to open-source project if e.g. this project is used for work and has some bug. And there are always bugs or inconveniences if you use something heavily. For some industries it is even hard for a developer not to be on Github, because a lot of software she uses is on github, and in a lot of cases the best way to fix the issue she's working on is to contribute to open-source project that caused this issue, instead of e.g. working around it by some hack.

I agree that discarding people without respectable github presence is bad (unless you're looking for a very specific kind of people, e.g. for marketing purposes). But I can see how not being on Github at all (even with minimal presence) could be a bad sign in some cases. Of course, industries are very different and this shouldn't be a general rule.