Magnum,
My opinion would be similar to others already stated: The NT reflected the times and the culture, which if we are to believe the time period of the writers, was compressed to a generation or so. But it's just an opinion.
The first time I read that beauty = symmetry I thought, that's crazy. But it is true. Symmetry also reveals strength, fertility, etc., whether it is a tree or a person. The more symmetrical, according to the experts, the better the DNA is for passing along to offspring and hence the more attractive that person is to one looking for a mate (whether they know it or not).
Those who study such things know it much better than I. But think about a beautiful tree. Almost always it is because of its symmetry, that which gives it strength from winds, rains, etc. also makes it beautiful to look at. If lightning or some other issue causes the tree to lose most/all of its branches on one side, it loses a lot of its beauty to our eyes. Nature requires symmetry for survival in many ways.
Sociologists and the like theorize that humans somewhat broke the cycle when our brains developed more fully. Rather than the biggest, baddest (and likely most symmetrical) male getting all the stuff and the girls, other guys used their brains to find ways to bring girls food and stuff so that they could mate with them.
It's the same today. We call it dating.