No, actually I think this is a fairly poor analogy. In your example, one is being asked to harm _another_ for their benefit. In the other, one is being asked to

No, actually I think this is a fairly poor analogy. In your example, one is being asked to harm _another_ for their benefit. In the other, one is being asked to harm _one’s self_ for their benefit. However terrible and painful the example is, abstractly, I believe people are free to decide what happens to themselves, but not to others. Murder is universally illegal, while prostitution, arguably, shouldn’t be, and isn’t in many places.