I don't see how "basic commodity required for life" is a necessary criteria for any ethical standards to apply at all. This is about trust, community and how to be a good project steward.
Of course the entitlement to volunteer work is also rude, and in my opinion worse.
I don't think this is a reason to never volunteer but you have to develop a thick skin, know where your lines are, and at some point politely but firmly say "no."