In Germany there is a legally recognised form of volunteering called Ehrenamt (honorary office), mostly used by non-profit organisations. It has benefits for taxes, gaining public funding, and such. E.g. if you are the primary caretaker of an elderly family member you can get unemployment benefits without having to look for work, since it is recognised as a public good.
The petition aims to recognise work on Open Source software as such an honorary office.
While true, a git history is also easily protected against fabrication. Require cryptographically signed commits and prevent contributors from force-pushing to the public repo and you should be good.