If you want any of this, why don't you found a Verein and have open source activities as the purpose?
All in all I an very much against this. Mostly because I think Ehrenämter, as they exist now, are pretty stupid and pointless and because I strongly believe the state should not get involved with this at all.
The petitioners seem to be blissfully unaware how civil service is recognized in Germany. Or they are all too much aware and want to undermine transparency requirements by asking for special treatment for open source developers. The charity principle requires to assume the former.