I think that the problem is that "open source" in itself is not volunteering.
Just like "masonry" is not volunteering, even though a mason could volunteer by building an orphanage pro bono. But when they build their own house, it's not volunteering.
I don't even think that being paid for building an orphanage counts as volunteering... does it?
If the thief keeps looting the full house of others sure. Even more so if the thief uses the loot to provide services you rely on and society as a whole has decided to give the thief the right to loot part of everyone's house.