The phrase, "work for a non-profit" implies some level of compensation. Had you instead said, "volunteer for a non-profit," then I would have understood that you were working in your spare time and for no pay.

> "why it should be interrupted by a constant treadmill on recruiter's rat race?"

Isn't this self imposed if you are the one applying for the job??? I don't get it, if some rando recruiter emails me a Hacker Rank test, I delete the email if I'm not interested...pretty simple. If I am interested, then I apply and that is no longer an "interruption"...or at least it is self imposed so there is no real reason to complain.