Why does almost every successful (large and long-lived) traditional culture in the world have homophobic undertones? Cultures can be thought of as evolutionary units. Cultures that accept gay people on average have lower birth rates and are ultimately outnumbered by neighboring homophobic cultures. We nevertheless stand at a unique point in history at which gay acceptance has risen. Why? Because the internet, widespread education, easy travel, and television empowered memes that compete on the basis of logic, philosophy, prosociality, and human decency. The culture produced by effective altruism is one of those memes. However, this unique moment in history has introduced never-before-seen selective pressures on our species that could push us back to being a less inclusive society.
I’m skeptical of the putative direction of causality implied by this paragraph. I do not think acceptance of homosexuality has such a big effect on fertility rates. Rather, it seems to me that declining fertility and acceptance of homosexuality are both downstream of technological and cultural progress, which raise living standards, spread universal and cosmopolitan culture, and reduce birth rates for the reasons you mention in your section “Why is this Happening?”. I doubt that homophobia is a significant cultural “advantage” in modern times, even if there were some sort of adversarial competition between progressive and old-fashioned societies, because adoption and technologies like IVF are enabling many same-sex couples to have children just like heterosexual couples can.
I’m skeptical of the putative direction of causality implied by this paragraph. I do not think acceptance of homosexuality has such a big effect on fertility rates. Rather, it seems to me that declining fertility and acceptance of homosexuality are both downstream of technological and cultural progress, which raise living standards, spread universal and cosmopolitan culture, and reduce birth rates for the reasons you mention in your section “Why is this Happening?”. I doubt that homophobia is a significant cultural “advantage” in modern times, even if there were some sort of adversarial competition between progressive and old-fashioned societies, because adoption and technologies like IVF are enabling many same-sex couples to have children just like heterosexual couples can.