Expanded

To back-track to the beginning, the purpose of the first flow chart was to demonstrate the staggering importance of race in basic attraction, defined in terms of group membership. Without necessarily addressing how race fits into the factors-of-attraction framework.
Which, to recap, is the empirically substantiated knowledge from psychology that the primary determinants of attraction (platonic as well as romantic) are similarity, proximity, and physical attractiveness.
So to look at the issue in terms of factors of attraction, we would think of it as a matter of racial similarity eclipsing all other dimensions of similarity, and also physical attractiveness.
To integrate the one theory into the other, we’d only have to recognize that “common group membership” is a dimension of similarity, and that race is obviously a type of group membership. That makes race a dimension of similarity.