Resegregation or Choice

In the article, "Teaching Against Idiocy", by Walter Parker, it touches on issues that students in Just Community schools face and deal with. One of the topics that they may deliberate on is whether or not cafeteria seating should be assigned randomly as an effort against resegregation. I understand the school's efforts for every culture, race, etc. to be intermingled, but why can't the students have a choice as to who they can spend their free time with to chat about academic and social issues? I find that we form relationships with people whose cultures reflect or our own, because we tend to have more in common. I don't feel this is necessarily resegregation or being prejudice against others. I am curious to know how others feel about this topic if it were an issue to be deliberated in your own school.