Replying to a many-world-like question

While the linked to blog post discussion is somewhat interesting it seems misleading to call it a 'many-world-like question'. In trying to extract the 'rationalist moral' from the link perhaps the best quote that I can extract is the preceding sentence:

from the hypothesis that the universe is infinite, it doesn’t logically follow that all possible Earth-like planets have to exist somewhere.

At a stretch the 'rationalist moral' could be the general principle 'Don't make logical errors just because infinity confuses you'. (I'd certainly endorse that as an often neglected insight!)