Why not just drop the whole white, black, yellow, brown, red, hispanic, asian, caucasian thing all together and just be male or female humans?
What do you mean drop? Should we drop "height" and just all be "medium"? Height is just a fact about people. For some things it's completely unimportant, for some other things it's very important. But either way it just *is*.
Despite the "social construct" people race is a real thing too. There are all sorts of things you can tell by people's race - whether they are susceptible to this disease or that disease, what there life expectancy is, how likely they are to go to jail. Sure, all statistical generalizations.
Culturally, it's an even more important marker, though. Meet a black man today and there is a 19 in 20 chance that he voted for Obama.
I think the longing for race to be invisible is a white pathology, based on misplaced white guilt. Blacks don't want race to go away. Go watch the Jamie Foxx video: blacks are (and again there is an exception to prove the rule out there) thrilled to be black, revel in their race.
All the Chinese I know are happy they are Chinese, and think the Chinese are the best race, the biggest race, the oldest race, the greatest of the Asian races, etc.
Whites used to think that way too. But now our kids are fed Sesame Street and "we're all equal" as little kids, and then Howard Zinn - the evil white oppressor, the history of Bad Things White People Did all through elementary and high schools, and so by they time they are 20 they either wish they were some other race (sometimes going so far as pretending that they are Indians like the Lady Senator from Massachusetts) or just wish that the "race would all go away".
Race isn't going away anymore than height - though the white race is certainly declining, and as so many of our markers are recessive the fashion for intermixing is certainly harder on whites than other races.
BTW: If we followed your thought, why should we have male and female - everyone should just be genderless. We should all identify as androgynous / transgender, eh?
My preference isn't for race to go away, it's for Whites to get a renewed sense of pride and racial solidarity, just like all the other races. Why no "white caucus" in the House? The black caucus is not going anywhere, that's for sure. Right now we alone, as a race, are unilaterally disarmed, and we are pushed around just like every other unarmed group in history. Not good. Time to arm up, man up and stand up!