Why are those who disagree with miscegenation viewed with mild contempt?

I'm going to start by quoting from Hebrew scripture in the King James Version. /Genesis 24:3 And I will make thee swear by the LORD, the God of heaven, and the God of the earth, that thou shalt not take a wife unto my son of the daughters of the Canaanites, among whom I dwell/ Looking at this page, one could replace Canaanites with any specific ethnic group living in a suburban metropolitan area. In the United States it seems as though there is a strong push against traditional family values and miscegenation is one of them. I presented this idea to my colleagues and it seems that some of them are so numbed down by media they can't grasp why it is important to appreciate your own kind by not spreading the mixing of races. I can see why the majority of those who support anti-miscegenation try so fervently to go against their own genes. Before someone implies "we are more than 90% identical by DNA" consider this: human beings in pre-historic times made a choice of how and where they wanted to live to cultivate their own way of life. Because of this rich expanse of varying origins come different types of man and woman. I'm speaking to those who are trying to undo the "Curse of Ham" by means of imposing an Anti-Miscegenation ideology instead of doing what is right by appreciating and desiring to build upon their own kind. Since parents are busy working shifts today's youth is exposed to ideas that come in conflict with their own culture whether it be that of European or Eastern. Thank you for sharing your ideas and answers and pardon any misconstrued sentiments regarding this matter.