Simple version:

Retention of juvenile traits and slowing of reproductive depth and rates, is reproductively desirable.

Symmetry and preservation of ideal ratios is reproductively desirable.

Races, subraces, and tribes evolved in different environments where different rates and depths of maturity were beneficial, and some where they were harmful.

All races, subraces, and tribes contain members who retain juvenile traits, and who have the ideal proportions.

Some races and subraces and tribes contain a larger percentage of those with juvenile traits and ideal proportions.

In most cases features correspond with genetic and social class.

The size of the underclass determines the distribution of favorable traits. (Too many people at the bottom is harmful)

East asians and western europeans were in the most favorable conditions to evolve such traits, and reduce the size of the underclasses.

In other words: it’s not about how races look, it’s about the number of people in each race, subrace, or tribe who are less desirable. 😉