Let's say a merperson was raised in the absence of adult merpeople. Is there any way they could learn in one lifetime all of the different ways that a mer-society can take advantage of the sea? Genetic and cultural inheritance are both really important.

In all seriousness though, Tolkien's worldview was more medieval than colonial. The north/south, high/low dynamic is a different dimension than the relationship between Europe and North Africa. It's altitude rather than longitude. Putting everything in relationship to the heavens is a touchstone of medieval culture.

Twisted (cf the article's 'ugly') things were considered a visual metaphor for evil by Dante. Dante imagined that beings who were living out their function/purpose with excellence were rooted in the ground but pointed at the stars [ie 'straight]. Men and women who succumbed to temptation were pointed at the stars by design but through concupiscence [getting caught up/busy; becoming obsessed/addicted], such 'crooked' people were turned inward on themselves and could no longer appreciate the things above them.