I think your reading of that bit you quoted is extremely uncharitable. I don't see where urbit is passing pronouncements on anyone's "worthiness". The way I read that quote is, "an urbit planet is server software, and there are way less than 4B people with a server to run it on."
That's beside the point, though. Using scarcity to create value is not "extremely unconventional"; it's about the most ho-hum idea in Urbit. If you want a 128-bit address, you can use those in Urbit just fine. The only difference is that they don't have a default-positive reputation (where "reputation" is an abstract concept -- in practice, e.g. some channels wouldn't let 128-bit address post comments)
[0] https://www.census.gov/population/international/data/idb/wor...
If you aren't an independent adult, and you don't need or even shouldn't have unconditional digital freedom (no one's 8-year-old daughter needs unconditional digital freedom), a moon from someone else's planet is fine. (Even most of today's independent adults don't complain enough about being Facebook's moons.)
It's literally a bullet in their "objections" post.