Northwestern University Systems Administrator interview questions

A recruiting company called me for position at Northwestern. Interviewed for Northwestern which was relatively simple questions . The experience required was only 3 yrs , I had more than 6 yrs of experience. I was asked personality or scenario questions only nothing technical. The interviewers said they would reply by tommorrow , after 2 days when I did not hear back I called staffing company and they contacted them back. After some time they informed that I don’t have enough experience for that role and would like to proceed with other candidate. How did they determine I did not have experience when no technical questions were asked ? More over when they asked for 3 yrs of experience they were getting person with 6 yrs of experience which is already double where they expecting a candidate of 25 yrs of experience .