Legalizing X doesn’t just mean you can do X if you want to. Legalizing X helps normalize X, and gives other people license to expect you to do X. When child labor was legal, society could expect the poor to rent their children to mines and factories. Were the poor forced to rent their children at gunpoint? Well, no. They were coerced by economic circumstance, as usual.
If you legalize a way to mitigate desperate poverty, then the desperately poor can be expected to do that. And those who refuse will be seen as unsympathetic and unworthy of assistance. After all, how can you say you’re really poor? You have an idle ten-year-old and a perfectly good spare kidney!
Counterpoint 1: this sounds like a deliberate adoption of the bystander effect. The more people know about a problem, the less responsible I am to do anything about it...
Counterpoint 2: many problems require collective action, which requires the problem be widely known.