For example, I know some people who argue that Christian cultures are objectively better at making a working, prosperous, and safe society, and that therefore we should work to convert immigrants and their native cultures to Christianity.

Strictly enforced monogamy by Christianity coupled with strong rules against inbreeding (extending beyond cousins!) perhaps are something that fits the bill . Obviously modern Western Christianity seems to be slowly abandoning both, with the exception of fundamentalists.

I'm pretty sure that if one could push a button that would convert the non-Islamic population of Africa to Christianity instantly one would see an improvement in the measurable standard of living. Doing the same for the Muslim population might or might not (one would have to weight its effect on the spread of AIDS vs. the gain women would enjoy).

Also I think I need to point out that:

• African tribal religion > Christianity > Atheism
• African tribal religion > African tribal religion > Atheism

Will probably produce different societies, not to mention values. In many respects Western "humanism" is deeply infected with "Christian" memes, it partially serves as a refuge for atheists to shepperd the ones they liked from Christianity into it.