My whole life is diverse - being a non traditional student I don't define my self by my college attendance and who sits in the class with me. My college doesn't seem to come down to the wire like that to add (makes me wonder just how many schools have to pick and choose students and can't just take them all - and why) Anyone who's in my college is in because they applied and not because of the color of their skin.
In the future: my children shouldn't be given special privilege because they look different - They should be given consideration because of their intelligence, creativity - these other skills and elements of being a solid student. Things that can be nurtured, furthered and shaped via schooling, education and homework - etc etc etc. I'm not about to encourage my children to think that their race and skin tone is EVER a determining or defining factor for them.
By the time you get to college you should be a set individual who doesn't need further 'exposure' but rather the ability to attend if you'd like and want.
I don't think anyone is arguing that people should "define themselves by their college attendance and who sits in class with them". What most people, including myself, seem to be trying to communicate is the value that a diverse college atmosphere had to our college experience and can add to a college in general and using that as an explanation for why we believe diversity is a legitimate goal for universities to reach.
While it's an interesting position that 18 year olds should be "set individuals who don't need further exposure", it's not an accurate representation of reality. An eighteen year old is not even close to a set individual. Most people, including me, leave college very different people than they were when they entered. Moreover, while I don't believe anyone "needs" exposure, I recognize that interacting with people of different races, religions, orientations, backgrounds and nationalities gives one a more whole perspective of the world than one would have by only interacting inside and outside of class with straight, white, Christian, middle class Americans.
Moreover, while on the one hand, it's a noble goal to make sure that your child doesn't think their "race and skin tone is ever a determining or defining factor" for them, on the other hand, it's not an accurate portrayal of reality. Race does not "define" a child insofar as it does not determine their value, inherent abilities and potential. With those factors, all "races" are equal. However, race like religion, nationality and sexuality certainly has an impact on how the rest of the world treats them and in turn, how they view the world. Many colleges are starting to understand this.
While academic potential, creativity, curiosity and other similar factors should be the primary factors in determining applicants, there is still a lot to be said for "personal details" being secondary factors. Colleges, particularly liberals arts and higher ranked colleges, like for their campuses to be centers for exchanging ideas and they like their students to be exposed to many different types of ideas because it makes them better students, citizens and workers. You're going to get many more ideas on a campus with a great mix of races, nationalities, orientations, backgrounds and religions than you will otherwise.