It's not about the moral gravity but about an illustrative example of a particular category of people who have access to devices where buying stuff is possible - children. Our marketplace has at least some customers that clearly are unable to protect themselves and need protection, e.g. these children. This places some contraints on the properties that this marketplace must have - e.g. reversals must be possible without undue burden. And this places some limitations on what technologies can/can't provide these properties and thus would/wouldn't be suitable.

It's a good point, about children and reversing transactions.

Even when everyone's an adult, consumer protections can be very important -- e.g. to prevent things like lending crises.

Invoking family to make an ethical point is something I see often, in many different circumstances.

How does being an orphan make one care less about humanity?

Personally, I want orphans (as defined as minors with no living parents) to be well-cared for regardless, either by relatives or by an outside agency ("orphanage" or foster home).

Absolutely, that's my point. We should care about people, period. Whether one has a family should be irrelevant to the question of how to engineer a society.

Thanks for clarifying. I agree 100%.