The type of student who should not attend Columbia University, is a student who doesn't desire to grow. If a student plans on leaving the university exactly as he or she was when they entered, then they should attend elsewhere. Columbia is a transformative experience, but the will to change must be internally present in the student.
The students who should not attend this school are the ones who have no ambition, and/or feel that they can do everything on their own. The ones who have no sense of community, or feel they can accomplish everything alone. No success will be gained by trying to shoulder academia at this school alone.
It is simple to me that any student that does not like the city environment will not thrive at Columbia. In the heart of New York City you are constantly surrounded by a plethora of people, cars, and buildings. Some thrive in this fast-paced environment but some need more nature in their lives than the confines of Central Park. If this is the case Columbia may not be fore you.
If you prefer a quiet atmosphere and a smaller student body, Columbia would not be a fit. Being in the city and a large classroom setting requires a personality of someone who is self-sufficient and highly organized.
If you do not thrive in a, at times, hectic student environment and if you like smaller colleges this is not the place for you