The Puzzling diversity of NU (from an Interview with potential ISSI director)

Yesterday I had the privilege of being on a student committee helping in the interviewing process for our new ISSI (international students and scholars institute) director. The institute is one of the largest in the US representing more than 4500 international students on campus, so the position is important, and the finances are huge. One issue kept coming up as we were trying to pinpoint some of the major issues that the new director is expected to focus on, and it reminded me of something we studied not so long ago.
NU is one of the most diverse (in terms of nationalities and ethnicities) in the US. But a puzzling thing is that this seems to exclude Americans on campus. While discussing this a lot of input from students, in addition to my personal experience indicate that Americans do not participate in almost any of the numerous events, including a 2 month-long carnvale (the longest in the US). In the orientation program only 1 (out of 70) last year was American. Many Americans when asked (and I tried this today), about what the ISSI stands for or does seemed to be completely clueless. This is despite the huge budget dedicated to advertising in all possible forms and locations. What adds to the puzzle, I think, is that NU has quite a large (in terms of enrollment) program in international affairs, and an equally large study aboard program. Americans are indeed interested in international matters, so why aren't they active with the international community on campus?
I think the issue has multiple interesting factors.
-The idea of the big sorts, and that the more diverse the overall environment the less diverse your own social network which is basically homophily in its purest forms. Going to these events means leaving your comfort zone (and network). forming lasting relationships (such as being part of the orientation program for 2 months means basically altering your network by adding some new weak ties and interacting with them) means you must oppose willingly oppose homphily (cost) to gain other things which might not be as high in their minds (or they don't realize the benefit yet)
-A difference between embracing diversity in ideas (intellectually) in the classroom or in study abroad with similar students (i.e. Americans), and doing the actual (physical thing) by going to the events and forming relationships and maintaining them.
-An interesting observation I heard from a grad student in higher education is that some American students are simply tired of hearing about diversity and so they reject it all together in college.
Our potential new director was kind of using network terminology when he said that having all of these programs/int students (the weak ties) is not enough. Segregation (i.e. homophily) will always take place, and so the main question is how to reach out in a subtle yet affective way to integrate both communities. Obviously dealing with social networks is not like computer networks where adding more/new ties is rather easy, and I think a school that has gone as far as NU in trying to solve this with no avail might, unfortunately, reinforce the concept of the big sorts. I'm afraid this might lead to extreme behaviors at some point (as was mentioned in going to the extreme) which our director called potential campus-cultural-wars. More clustering happens (in the classroom, dorms, labs,..) and dislike of the other spreads as stereotypes increase and diversity becomes a burden which is the opposite of what is should do. There are elements of exaggeration here, but maybe also some truth that the future will tell us about if we don't take some action.