Every school interviews a good chunk more people than they admit every year. They have to prefer certain applicants over others, because interviews aren't a level playing field. If they interview 325 students and only admit 250 each year, then there's something going on.
The only reason I can think of behind this, is if they're hoping a sub-par applicant will prove himself, or it's only to artificially continue the tradition of the interview. (some law schools have done away with interviews alltogether). Adcoms realize the limitations of interviews and know that they cannot assess everything about an applicant in 30 minutes or an hour. If this were true, then you wouldn't have physicians who get busted for sexual assault or any other personality-related problem that may have been detectable in the interview. Very few people act themselves at the interviews.
Thus, unless you stand out as some exemplary person at an interview, your admission is probably dictated more by your numbers than anything else.