By your reasoning, a doctor who volunteers to provide free care to people has no duty of care to those patients. This is patently absurd - ethics and norms are a large part of what constitutes a professional.

And for what it's worth, I have flagged your comment for the inevitable pointless bickering it has precipitated. While applying reductionist frameworks and seeing where they lead is a necessary part of an individual's path to understanding, please avoid pushing ignorant assertions ("there is no duty here") as if they might constitute well reasoned truths.