I highly doubt that cape verde was at any time an egalitarian society, meaning that an elite few were responsible for running the entire country. This basically means that those few were able to mold a society that benefits them the most and the easiest way to do that is with division. Doesnt get more divided than 17 different classifications..
Dont just look at the effect, look at the cause people
The country isnt divided like that though. People may identify based on some skin shade type ish but really its not that deep when interacting with one another. There are only 500 thousand people in Cape Verde. We get along from the straight up African Cv's to the half breeds to the barely African type cacs. Even a fakkit like Victor Von Doom would get love in CV but they wouldnt allow him to call himself a black man