Would you also say "shame on you" to anyone who procreates in a country with a lower standard of living than the wealthier countries on this planet? After all, aren't those parents subjecting their children to a life with more hazards / less opportunities?

Only very few places on Earth are truly that shitty that I would doubt people's sanity for raising children there. Active war zones and areas affected by climate change for example, and to no one's surprise people risk their lives to escape from those. Even in a refugee camp, their children would still lead a life that is magnitudes easier and more pleasurable than on a Mars colony.

> Would you also say "shame on you" to anyone who procreates in a country with a lower standard of living than the wealthier countries on this planet?

I would not hesitate to do so to any parents that leave a perfectly functional society to raise children as subsistence farmers in an smog-choked, irradiated, arid clime. Opting to raise your children under worse conditions than those one grew up under, and has access to is despicable and selfish.

I'm talking about freedom of choice:

>Do we build a wall around Earth and stop them as "illegal aliens"?

This was of course an analogy to the United States, where we put up barriers to prevent emigrants from seeking a better life here.

There's no shame in procreation, but there's shame in trapping people forever in a place where they no longer want to live.

You wouldn't even need an Iron Curtain: moving to Earth, however much they want to, would kill them.

> moving to Earth, however much they want to, would kill them

That is an assumption but far from a certainty.

Uncertainty does not help you here.