But the real question is why does skin colour really matter?
Because Dominican Republic is the only mulatto society in the world, and as such, mulatto issues take a national precedence unlike anywhere else in the world. Except, of course, in mulatto minorities in other countries, including the U.S. - despite the complete negation of anything mulatto in those countries.
Do your research on Haiti, Jamaica, Cuba, Colombia, et al; once you hit the mulatto group, the same issues pop up.
As for why?
I used to wonder why mulattoes were plagued by this dilemma and the only conclusion I have reached is that mulattoes are denied identifying as mulattoes everywhere in the world. They are either pushed towards being white or black, being mixed is almost cursed and anyone identifying as mixed is perceived as confused, ridiculous, so on and so forth.
In the US, Jim Crow laws and anti miscegenation laws were passed to control the mulatto population. Mulatto were relegated to the black category in order to keep them in place, since the only group that threatened white society was the mulatto, whose existence was proof that the black/white racial categories and the concept that God didn't want people to mix was simply NOT TRUE.
In the US, what essentially was a mulatto issue has been taught to the entire AA community, but that is because mulattoes were relegated to such level, the level of slaves to keep white society in tact, in a dominant position, and in peace.
In countries where whites were the minority, the opposite is true.
The result: mulattoes all over the world are told to be anything other than mulattoes. This confuses many mulattoes and thus, re-enforces the Tragic Mulatto myth.
Call it the oppression of the mulattoes, and this oppression is perpetrated by whites, blacks, and mulattoes that identify as either white or black (or indio) which is almost all of them.
Here is a good reading regarding how Mulattoes have been controlled. This focuses on the US, but similar things occurred in other countries:
The Modern Mulatto
-NALs